310 CMR, § 22.07E

Current through Register 1536, December 6, 2024

Section 22.07E - Disinfection Byproducts, Disinfectant Residuals and Disinfection Byproduct Precursors

(1)MCLs for Disinfection Byproducts. The Maximum Contaminant Levels for Disinfection byproducts of 310 CMR 22.07E apply only to Community Water Systems and Non-transient Non-community Water Systems which add a chemical Disinfectant (oxidant) to the water in any part of the drinking water treatment process. The MCLs are as follows:

Disinfection Byproduct	MCL (ma/l)
Total Trihalomethanes (TTHM)	0.080
Haloacetic (Acids Five) (HAA5)	0.060
Bromate	0.010
Chlorite	1.0

Total Trihalomethanes are the sum of the concentrations of bromodichloromethane, dibromochloromethane, tribromomethane (bromoform) and trichloromethane (chloroform) expressed in milligrams per liter (mg/l). Haloacetic acids are the sum of the concentrations of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid expressed in milligrams per liter (mg/l).

(a)Compliance Dates for CWSs and NTNCWSs. Surface Water and Groundwater under the Direct Influence of Surface Water systems serving 10,000 or more persons must comply with 310 CMR 22.07E(1) beginning January 1, 2002. Surface Water and Groundwater under the Direct Influence of Surface Water systems serving fewer than 10,000 persons and systems using only groundwater not under the direct influence of surface water must comply with 310 CMR 22.07E(1) beginning January 1, 2004.

(b)TTHM and HAA5 - RAA Compliance.

Compliance Dates. Surface Water and Groundwater under the Direct Influence of Surface Water systems serving 10,000 or more persons must comply with 310 CMR 22.07E(1)(b) beginning January 1, 2002. Surface Water systems and Groundwater under the Direct Influence of Surface Water systems serving fewer than 10,000 persons and systems using only groundwater not under the direct influence of surface water must comply with 310 CMR 22.07E(1)(b) beginning January 1, 2004. All systems must comply with these MCLs until the date specified for Disinfection byproduct compliance in 310 CMR 22.07F(7).

(c)Stage 2 Disinfection Byproducts - LRAA Compliance.

Compliance Dates. The MCLs required under 310 CMR 22.07F for TTHM and HAA5 must be complied with as a Locational Running Annual Average at each monitoring location beginning the date specified for compliance in 310 CMR 22.07F(7)(c).

(2)MRDLs for Disinfectant Residuals. The maximum residual Disinfectant levels for the Disinfectant residuals of 310 CMR 22.07E apply to Community Water Systems and Non-transient Non-community Water Systems which add a chemical Disinfectant (oxidant) to the water in any part of the drinking water treatment process. In addition, the maximum residual Disinfectant level for chlorine dioxide applies to Transient Non-community Water Systems using chlorine dioxide as a Disinfectant or oxidant. The MRDLs are as follows:

Disinfectant Residual	MRDL (mg/l)
Chlorine 4.0 (as Cl₂).
Chloramines 4.0 (as Cl₂).
Chlorine dioxide	0.8 (as ClO₂).

Notwithstanding the MRDLs in 310 CMR 22.07E(2), systems may increase residual Disinfectant levels in the Distribution System of chlorine or chloramines (but not chlorine dioxide) to a level and for a time necessary to protect public health, to address specific microbiological contamination problems caused by circumstances including, but not limited to, distribution line breaks, storm run-off events, source water contamination events, or cross connection events.

(3)Compliance Dates.

(a) Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water that serves 10,000 or more persons shall comply with the requirements of 310 CMR 22.07E beginning January 1, 2002.

(b) Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water that serves fewer than 10,000 persons and each Supplier of Water who uses only a groundwater source not under the direct influence of surface water shall comply with the requirements of 310 CMR 22.07E beginning January 1, 2004.

(c) Each Supplier of Water that plans to install granular activated carbon (GAC) or membrane technology to comply with the MCLs in 310 CMR 22.07E(1) may apply to the Department for an extension of up to 24 months past the dates in 310 CMR 22.07E(3)(a) and (b), but not beyond December 31, 2003. In granting the extension, the Department will require the system to issue public notice in accordance with 310 CMR 22.16. The notice shall include the length of the extension, the mandatory health effects language for Disinfection byproducts and the anticipated schedule for the construction and implementation of the new treatment processes. The Department may also require the Supplier of Water to perform an engineering study to optimize the current treatment processes to minimize the formation of Disinfection byproducts during the period of the extension.

(4)Disinfection Byproducts BATs.

(a) The EPA Administrator, pursuant to the federal Safe Drinking Water Act, § 1412 has identified the following as the best technology, Treatment Techniques, or other means available for achieving compliance with the Maximum Contaminant Levels for Disinfection byproducts identified in of 310 CMR 22.07E(1):

Disinfection Byproduct	Best Available Technology
TTHM	Enhanced Coagulation or Enhanced Softening or GAC10, with chlorine as the primary and residual Disinfectant.
HAA5	Enhanced Coagulation or Enhanced Softening or GAC10, with chlorine as the primary and residual Disinfectant.
Bromate	Control of ozone treatment process to reduce production of bromate.
Chlorite	Control of treatment processes to reduce Disinfectant demand and control of Disinfection treatment processes to reduce Disinfectant levels.

(b) The EPA Administrator, pursuant to the federal Safe Drinking Water Act, § 1412, 40 CFR 141, hereby identifies the following as the best technology, Treatment Techniques, or other means available for achieving compliance with the Maximum Contaminant Levels for TTHM and HAA5 identified in 310 CMR 22.07E(1) for all systems that disinfect their source water:

Disinfection byproduct	Best Available Technology
Total Trihalomethanes (TTHM) and Haloacetic (Acids Five) (HAA5).	Enhanced Coagulation or Enhanced Softening, plus GAC10; or nanofiltration with a molecular weight cutoff <=1000 Daltons; or GAC20

(c) The EPA Administrator, pursuant to the federal Safe Drinking Water Act, § 1412, 40 CFR 141, hereby identifies the following as the best technology, Treatment Techniques, or other means available for achieving compliance with the Maximum Contaminant Levels for TTHM and HAA5 identified in 310 CMR 22.07E(1) for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive:

Disinfection Byproduct	Best Available Technology
Total Trihalomethanes (TTHM) and Haloacetic (Acids Five) (HAA5).	Systems serving >=10,000: Improved Distribution System and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance
Systems serving <10,000: Improved Distribution System and storage tank management to reduce residence time.

(5)Disinfectant Residuals BATs. The EPA Administrator, pursuant to the federal Safe Drinking Water Act, § 1412, 40 CMR 141, has identified the control of treatment processes to reduce Disinfectant demand and the control of Disinfection treatment processes to reduce Disinfectant levels as the best technology, Treatment Techniques, or other means available for achieving compliance with the maximum residual Disinfectant levels for Disinfectant residuals identified in 310 CMR 22.07E(2).

(6)Analytical Requirements.

(a) Each Supplier of Water shall use only the analytical method(s) specified in 310 CMR 22.07E(6), or their equivalent as otherwise approved by EPA for monitoring under 310 CMR 22.07E and 22.07F, to demonstrate compliance with the requirements of 310 CMR 22.07E and 22.07F. These methods are effective for compliance monitoring as of February 16, 1999 unless a different effective date is specified in 310 CMR 22.07E(6) or by the Department.

(b) The methods described in 310 CMR 22.07E(6)(c) through (e) are contained within the following documents: EPA Method 552.1 is in Methods for the Determination of Organic Compounds in Drinking Water - Supplement II, USEPA, August 1992, EPA/600/R-92/129 (available through the National Technical Information Service (NTIS), PB92-207703). EPA Methods 502.2, 524.2, 551.1, and 552.2 are in Methods for the Determination of Organic Compounds in Drinking Water - Supplement III, USEPA, August 1995, EPA/600/R-95/131 (available through the NTIS, PB95- 261616). EPA Method 300.0 is in Methods for the Determination of Inorganic Substances in Environmental Samples, USEPA, August 1993, EPA/600/R-93/100 (available through the NTIS, PB94-121811). EPA Methods 300.1 and 321.8 are in Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1, USEPA, August 2000, EPA 815-R-00-014 (available through NTIS, PB2000-106981. EPA Method 317.0, Revision 2.0, Determination of Inorganic Oxyhalide Disinfection By-products in Drinking Water Using Ion Chromatography Incorporating the Addition of a Postcolumn Reagent for Trace Bromate Analysis, USEPA, July 2001, EPA 815-B-01-001, EPA Method 326.0, Revision 1.0, Determination of Inorganic Oxyhalide Disinfection By-products in Drinking Water Using Ion Chromatography Incorporating the Addition of a Suppressor Acidified Postcolumn Reagent for Trace Bromate Analysis, USEPA, June 2002, EPA 815-R-03-007, EPA Method 327.0, Revision 1.1, "Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidase with Detection by Visible Spectrophotometry", USEPA, May 2005, EPA 815-R-05-008 and EPA Method 552.3, Revision 1.0, "Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection, " USEPA, July 2003, EPA-815-B-03-002 can be accessed and downloaded directly on-line at http://www.epa.gov/safewater/methods/sourcalt.html. EPA Method 415.3, Revision 1.1, "Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water", USEPA, February 2005, EPA/600/R-05/055 can be accessed and downloaded directly on-line at www.epa.gov/nerlcwww/ordmeth.htm. Standard Methods 4500-Cl D, 4500-Cl E, 4500-Cl F, 4500-Cl G, 4500-Cl H, 4500-Cl I, 4500-ClO2 D, 4500-ClO2 E, 6251 B, and 5910 B shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 19^th or 20^th Editions, American Public Health Association, 1995 and 1998, respectively. The cited methods published in either edition may be used. Standard Methods 5310 B, 5310 C, and 5310 D shall be followed in accordance with the Supplement to the 19^th Edition of Standard Methods for the Examination of Water and Wastewater, or the Standard Methods for the Examination of Water and Wastewater, 20^th Edition, American Public Health Association, 1996 and 1998, respectively. The cited methods published in either edition may be used. Copies may be obtained from the American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. Standard Methods 4500-Cl D-00, 4500-Cl E-00, 4500-Cl F-00, 4500-Cl G-00, 4500-Cl H-00, 4500-Cl I-00, 4500-ClO2 E-00, 6251 B-94, 5310 B-00, 5310 C-00, 5310 D-00 and 5910 B-00 are available at http://www.standardmethods.org or at EPA's Water Docket. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that are IBR-approved. ASTM Methods D 1253-86 and D 1253-86 (Reapproved 1996) shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 1996 or any ASTM edition containing the IBR-approved version of the method may be used. ASTM Method D1253-03 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2004 or any ASTM edition containing the IBR-approved version of the method may be used. ASTM Method D 6581-00 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2001 or any ASTM edition containing the IBR-approved version of the method may be used; copies may be obtained from the American Society for Testing and Materials International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.

(c)Disinfection Byproducts.

1. Each Supplier of Water shall measure Disinfection byproducts by the methods (as modified by the footnotes) listed in the following table:

APPROVED METHODS FOR DISNFECTION BYPRODUCT COMPLIANCE MONITORING

Contaminant and methodology¹

EPA method

Standard Method SM online⁹ ASTM method³

TTHM

P&T/GC/ElCD& PID

P&T/GC/MS

LLE/GC/ECD

502.2⁴

524.2, 524.3¹⁰,

524.4¹⁵, 551.1

HAA5

LLE (diazomethane)/GC/ECD

SPE (acidic methanol)/GC/ECD

LLE (acidic methanol)/GC/ECD

Ion Chromatography Electrospray

Ionization Tandem Mass Spectrometry

(IC-ESI-MS/MS)

HAA5

LLE(diazomethane)/GC/ECD

SPE

--------------

552.1⁵

552.2, 552.3

6251 B^{2, 5, 11}

6251 B-94

Bromate

Ion chromatography

Ion chromatography & post column reaction

IC/ICP-MS

Ion Chromatography Electrospray

Ionization Tandem Mass Spectrometry

(IC-ESI-MS/MS)

Chemically Suppressed Ion Chromatography

Electrolytically Suppressed Ion Chromatography

300.1, 302.0^{6, 13}

317.0 Rev. 2.0⁶,

326.0 ⁶

321.8^6,7

557^{6, 12}

----------------

D 6581-00³

D6581-08A¹⁴

D6581-08B¹⁴

Chlorite

Amperometric titration Spectrophotometry Ion chromatography

Chemically Suppressed Ion Chromatography

Electrolytically Suppressed Ion Chromatography

-------------

327.0 Rev 1.1⁸ 300.0, 300.1, 317.0

Rev 2.0, 326.0

4500-ClO2 E^2, 8

-----------------

-------------------

4500-ClO₂ E-008

----------------

D 6581-00³

D 6581-08 A¹⁴

D 6581-08 B¹⁴

Chlorite - daily monitoring as prescribed in 310 CMR 22.07E(7)(b)2.a.i Amperometric Titration

4500-ClO2 E¹¹

¹ P&T = purge and trap; GC = gas chromatography; ElCD = electrolytic conductivity detector; PID= photoionization detector; MS = mass spectrometer; LLE = liquid/liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; IC = ion chromatography, ICP-MS=inductively coupled plasma/mass spectrometer.

² 19^th and 20^th editions of Standard Methods for the Examination of Water and Wastewater, 1995 and 1998, respectively, American Public Health Association; either of these editions may be used.

³ Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01.

⁴ If TTHMs are the only analytes being measured in the sample, then a PID is not required.

⁵ The samples must be extracted within 14 days of sample collection.

⁶ Ion chromatography & post column reaction or IC/ICP-MS must be used for monitoring of bromate for purposes of demonstrating eligibility of reduced monitoring, as prescribed in 310 CMR 22.07E(7)(b)3.b.

⁷ Samples must be preserved at the time of sampling with 50 mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days.

⁸ Amperometric titration may be used for routine daily monitoring of chlorite at the entrance to the Distribution System, as prescribed in 310 CMR 22.07E(7)(b)2.a.i. Ion chromatography shall be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the Distribution System, as prescribed in 310 CMR 22.07E(7)(b)2.a.ii. and (b)2.b.

⁹ The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.

¹⁰ EPA Method 524.3, Version 1.0 Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry, June 2009. EPA 815-B-09-009. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html.

¹¹ Standard Methods for the Examination of Water and Wastewater, 21^st edition (2005). Available from American Public Health Association, 800 I Street, NW., Washington, DC 20001-3710.

¹² EPA Method 557. Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS), August 2009. EPA 815-B-09-012. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html.

¹³ EPA Method 302.0. Determination of Bromate in Drinking Waters using Two-dimensional Ion Chromatography with Suppressed Conductivity Detection, September 2009. EPA 815-B-09-014. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html.

¹⁴ Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 or http://astm.org. The methods listed are the only alternative versions that may be used.

¹⁵ EPA Method 524.4, Version 1.0. Measurement of Purgeable Organic Compounds in Water by Gas Chromatography/Mass Spectrometry using Nitrogen Purge Gas, May 2013. EPA 815-R-13-002. Available at http://water.epa.gov/drink.

2. Analysis under 310 CMR 22.07E(6) for Disinfection byproducts shall be conducted by laboratories that have received certification by EPA or the Department, except as specified under 310 CMR 22.07E(6)(c)3.

3. A party approved by EPA or the Department shall measure daily chlorite samples at the entrance to the Distribution System.

(d)Disinfectant Residuals.

1. Each Supplier of Water shall measure the Residual Disinfectant Concentration for free chlorine, combined chlorine (chloramines), and chlorine dioxide by the methods listed in the following table:

APPROVED METHODS FOR DISINFECTANT RESIDUAL COMPLIANCE MONITORING

Methodology	Standard Method (19^th, 20^th or 21^st editions)	SM Online²	EPA method	ASTM Method	Residual Measured ¹
Methodology	Standard Method (19^th, 20^th or 21^st editions)	SM Online²	EPA method	ASTM Method	Free C1₂	Combined C1₂	Total C1₂	C1₂ O₂
Amperometric Titration	4500-Cl D	4500-Cl D-00	D 1253-86 (96), 03, D 1253-08⁴	X	X	X
Low Level Amperometric	4500-Cl E	4500-Cl	X
Titration	E-00
DPD Ferrous Titrimetric	4500-Cl F	4500-Cl F-00	X	X	X
DPD Colorimetric	4500-Cl G	4500-Cl G-00	X	X	X
Syringaldazine (FACTS)	4500-Cl H	4500-Cl H-00	X
Iodometric Electrode	4500-Cl I	4500-Cl I-00	X
DPD	4500-ClO₂ D	X
Amperometric Method II	4500-ClO₂ E	4500-Cl O₂ E-00	X
Lissamine Green	327.0	X
Spectrophotometric	Rev 1.1
Amperometric Sensor -	X	X
ChloroSense⁵
On-line Chlorine Analyzer	334.06	X	X

¹ X indicates method is approved for measuring specified Disinfectant residual. Free chlorine or total chlorine may be measured for demonstrating compliance with the chlorine MRDL and combined chlorine, or total chlorine may be measured for demonstrating compliance with the chloramine MRDL.

² The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.

³ Cl₂ = Chlorine, ClO₂ = Chlorine Dioxide.

⁴ Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 or http://astm.org. The methods listed are the only alternative versions that may be used.

⁵ ChloroSense. Measurement of Free and Total Chlorine in Drinking Water by Palintest ChloroSense, September 2009. Available at http://www.nemi.gov or from Palintest Ltd, 21 Kenton Lands Road, P.O. Box 18395, Erlanger, KY 41018.

⁶ EPA Method 334.0. Determination of Residual Chlorine in Drinking Water Using an On-Line Chlorine Analyzer, August 2009. EP A 815-B-09-013. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html.

2. Each Supplier of Water may also measure Residual Disinfectant Concentrations for chlorine, chloramines, and chlorine dioxide by using digital meter versions of DPD colorimetric test kits. Suppliers serving less than or equal to 3,300 persons may use non-digital meter DPD colorimetric test kits.

3. The Department approves all laboratory personnel (both in-house and at Department certified laboratories) as well as certified operators to conduct measurements of Residual Disinfectant Concentrations. All parties conducting these measurements shall be approved by the Department and shall be trained in the relevant methodology and/or the use of the relevant equipment and shall follow procedures outlines by the manufacturer of that equipment.

(e)Additional Analytical Methods. Each Supplier of Water who is required to analyze parameters not included in 310 CMR 22.07E(6)(c) and (d) shall use the following methods. A party approved by the Department as per 310 CMR 22.07E(6)(d)3. shall measure these parameters.

1.Alkalinity. All methods allowed in 310 CMR 22.06B(10) for measuring alkalinity.

2.Bromide. EPA Methods 300.0, 300.1, 317.0 Revision 2.0, 326.0, or ASTM D 6581-00.

3.Total Organic Carbon (TOC). Standard Method 5310 B (High-Temperature Combustion Method) or 5310 B-00 (High-temperature Combustion Method) or Standard Method 5310 C or 5310 C-00 (Persulfate-ultraviolet or Heated-persulfate Oxidation Method) or Standard Method 5310 D or 5310 D-00 (Wet-oxidation Method) or EPA Method 415.3 Revision 1.1or Revision 1.2. Inorganic carbon must be removed from the samples prior to analysis. TOC samples may not be filtered prior to analysis. TOC samples shall either be analyzed or shall be acidified at the time of sample collection to achieve pH less than or equal to 2.0 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified TOC samples shall be analyzed within 28 days.

4.Specific Ultraviolet Absorbance (SUVA). SUVA is equal to the UV absorption at 254nm (UV254) (measured in m-1 divided by the dissolved organic carbon (DOC) concentration (measured as mg/l). In order to determine SUVA, it is necessary to separately measure UV254 and DOC. When determining SUVA, systems shall use the methods stipulated in 310 CMR 22.07E(6)(e)4.a. to measure DOC and the method stipulated in 310 CMR 22.07E(6)(e)4.b. to measure UV254. SUVA shall be determined on water prior to the addition of Disinfectants/oxidants by the system. DOC and UV254 samples used to determine a SUVA value shall be taken at the same time and at the same location.

a.Dissolved Organic Carbon (DOC). Standard Method 5310 B or 5310 B-00 (High-temperature Combustion Method) or Standard Method 5310 C or 5310 C-00 (Persulfate-ultraviolet or Heated-Persulfate Oxidation Method) or Standard Method 5310 D or 5310 D-00 (Wet-oxidation Method) or EPA Method 415.3 Revision 1.1 or Revision 1.2. DOC samples shall be filtered through a 0.45 µm pore-diameter filter as soon as practical after sampling, not to exceed 48 hours. After Filtration, DOC samples shall be acidified to achieve pH less than or equal to 2.0 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified DOC samples shall be analyzed within 28 days of sample collection. Inorganic carbon must be removed from the sample prior to analysis. Water passed through the filter prior to Filtration of the sample shall serve as the filtered blank. This filtered blank shall be analyzed using procedures identical to those used for analysis of the samples and shall meet the following criteria: DOC < 0.5 mg/L. Acidified DOC samples shall be analyzed within 28 days of sample collection.

b.Ultraviolet Absorption at 254 nm (UV254). Standard Method 5910 B or 5910 B-00 (Ultraviolet Absorption Method) or EPA Method 415.3 Revision 1.1 or Revision 1.2. UV absorption shall be measured at 253.7 nm (may be rounded off to 254 nm). Prior to analysis, UV254 samples shall be filtered through a 0.45 µm pore-diameter filter. The pH of UV254 samples may not be adjusted. Samples shall be analyzed as soon as practical after sampling, not to exceed 48 hours.

5. pH. All methods allowed in 310 CMR 22.06B(10) for measuring pH.

6.Magnesium. All methods allowed in 310 CMR 22.06B(10)(a) for measuring magnesium.

(7)Monitoring Requirements.

(a)General Requirements.

1. Each Supplier of Water shall take all samples during normal operating conditions.

2. For the purpose of determining the minimum number of required TTHM and HAA5 samples, the Department may allow multiple wells drawing water from the same aquifer but entering the Distribution System at different locations to be considered one treatment plant. Upon written request from a Supplier of Water, the Department will make this determination based on the following criteria:

a. The wells must be shown to be in the same aquifer using Department GIS and USGS information.

b. The wells must be treated in the same fashion or with processes that can be shown to be equivalent with respect to the potential to form Disinfection byproducts.

c. TOC samples from each well under consideration, taken during August, must have comparable results.

3. Each Supplier of Water shall monitor in accordance with the monitoring plan required under 310 CMR 22.07E(7)(f).

4. Each Supplier of Water may use only data collected under the provisions of 310 CMR 22.07E to qualify for reduced monitoring.

5. Each Supplier of Water who qualifies for reduced monitoring shall obtain Department approval prior to altering sampling practices.

6. Systems must collect both TTHM and HAA5 samples at the same frequency at each monitoring location.

(b)Monitoring Requirements for Disinfection Byproducts.

1.TTHM and HAA5.

a.Routine Monitoring. Each Supplier of Water shall monitor at the frequency indicated in the following table:

Routine Monitoring Frequency for TTHM and HAA5

Type of system	Minimum monitoring frequency	Sample location in the Distribution System
Systems using Surface Water or Groundwater Under the Direct Influence of Surface Water serving at least 10,000 persons.	Four water samples per quarter per treatment plant.	At least 25% of all samples collected each quarter at locations representing maximum residence time. Remaining samples taken at locations representative of at least average residence time in the Distribution System and representing the entire Distribution System, taking into account number of persons served, different sources of water, and different treatment methods.¹
Systems using Surface Water or Groundwater Under the Direct Influence of Surface Water serving from 500 to 9,999 persons.	One water sample per quarter per treatment plant.	Locations representing maximum residence time.¹
Systems using Surface Water or Groundwater Under the Direct Influence of Surface Water serving fewer than 500 persons.	One sample per year per treatment plant during August.	Locations representing maximum residence time.¹ If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system shall increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the Distribution System, until the system meets reduced monitoring criteria in 310 CMR 22.07E(7)(b)1.d.
Systems using only groundwater not under direct influence of surface water using chemical Disinfectant and serving at least 10,000 persons.	One water sample per quarter per treatment plant.²	Locations representing maximum residence time.¹
Systems using only groundwater not under direct influence of surface water using chemical Disinfectant and serving fewer than 10,000 persons.	One sample per year per treatment plant during August.²	Locations representing maximum residence time.¹ If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system shall increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the Distribution System, until the system meets reduced monitoring criteria in 310 CMR 22.07E(7)(b)1.d.

¹ If a system elects to sample more frequently than the minimum required, at least 25% of all samples collected each quarter (including those taken in excess of the required frequency) shall be taken at locations that represent the maximum residence time of the water in the Distribution System. The remaining samples shall be taken at locations representative of at least average residence time in the Distribution System.

² Multiple wells drawing water from a single aquifer may be considered one treatment plant for determining the minimum number of samples required, with prior Department approval in accordance with criteria developed under 310 CMR 22.07E(7)(a)2.

b. A Supplier of Water may reduce monitoring, except as otherwise provided, in accordance with the following table:

Reduced Monitoring Frequency for TTHM and HAA5

If you are a . . .	You may reduce monitoring if you have monitored at least one year and your . .	To this level
System using Surface Water or Groundwater Under the Direct Influence of Surface Water serving at least 10,000 persons which has a source water annual average TOC level, before any treatment, <= 4.0 mg/l.	TTHM annual average <= 0.040 mg/l and HAA5 annual average <= 0.030 mg/l.	One sample per treatment plant per quarter at Distribution System location reflecting maximum residence time.
System using Surface Water or Groundwater under the Direct Influence of Surface Water serving from 500 to 9,999 persons which has a source water annual average TOC level, before any treatment, <= 4.0 mg/l.	TTHM annual average <= 0.040 mg/l and HAA5 annual average <= 0.030 mg/l.	One sample per treatment plant per year at Distribution System location reflecting maximum residence time during August. NOTE: Any system using Surface Water or Groundwater under the Direct Influence of Surface Water serving fewer than 500 persons may not reduce its monitoring to less than one sample per treatment plant per year.
System using only groundwater not under direct influence of surface water using chemical Disinfectant and serving at least 10,000 persons.	TTHM annual average<= 0.040 mg/l and HAA5 annual average <= 0.030 mg/l.	One sample per treatment plant per year at Distribution System location reflecting maximum residence time during August.
System using only groundwater not under direct influence of surface water using chemical Disinfectant and serving fewer than 10,000 persons.	TTHM annual average <= 0.040 mg/l and HAA5 annual average <= 0.030 mg/l for two consecutive years OR TTHM annual average <= 0.020 mg/l and HAA5 annual average <= 0.015 mg/l for one year.	One sample per treatment plant per three year monitoring cycle at Distribution System location reflecting maximum residence time during August, with the three-year cycle beginning on January 1^st following the quarter in which system qualifies for reduced monitoring.

c.Monitoring Requirements for Source Water TOC. In order to qualify for reduced monitoring for TTHM and HAA5 under 310 CMR 22.07E(7)(b)1.b, Surface Water and Groundwater Under the Direct Influence of Surface Water systems not monitoring under the provisions of 310 CMR 22.07E(7)(d) must take monthly TOC samples every 30 days at a location prior to any treatment, beginning April 1, 2008 or earlier, if specified by the Department. In addition to meeting other criteria for reduced monitoring in 310 CMR 22.07E(7)(b)1.b., the source water TOC Running Annual Average must be 4.0 mg/L (based on the most recent four quarters of monitoring) on a continuing basis at each treatment plant to reduce or remain on reduced monitoring for TTHM and HAA5. Once qualified for reduced monitoring for TTHM and HAA5 under 310 CMR 22.07E(7)(b)1.b., a system may reduce source water TOC monitoring to quarterly TOC samples taken every 90 days at a location prior to any treatment.

d. Each Supplier of Water on a reduced monitoring schedule may remain on that reduced schedule as long as the average of all samples taken in the year (for systems which shall monitor quarterly) or the result of the sample (for systems which shall monitor no more frequently than annually) is no more than 0.060 mg/l and 0.045 mg/l for TTHM and HAA5, respectively. Systems that do not meet these levels shall resume monitoring at the frequency identified in 310 CMR 22.07E(7)(b)1.a. (minimum monitoring frequency column) in the quarter immediately following the monitoring period in which the system exceeds 0.060 mg/l or 0.045 mg/l for TTHM or HAA5, respectively. For each Supplier of Water using groundwater not under the direct influence of surface water and serving fewer than 10,000 people, if either the TTHM annual average is > 0.080 mg/l or the HAA5 annual average is > 0.060 mg/l, the system shall go to increased monitoring identified in 310 CMR 22.07E(7)(b)1.a. (sample location in the Distribution System column) in the quarter immediately following the monitoring period in which the system exceeds 0.080 mg/l or 0.060 mg/l for TTHM or HAA5 respectively.

e. Each Supplier of Water on increased monitoring may return to routine monitoring if after at least one year of monitoring their TTHM annual average is 0.060 mg/l and their HAA5 annual average is 0.045 mg/l.

f. The Department may return a Supplier of Water to routine monitoring at the Department's discretion.

2.Chlorite. An owner or operator of Community and Non-transient Non-community Water Systems using chlorine dioxide, for Disinfection or oxidation, shall conduct monitoring for chlorite.

a.Routine Monitoring.

i.Daily Monitoring. Each Supplier of Water shall take daily samples at the entrance to the Distribution System. For any daily sample that exceeds the chlorite MCL, the supplier shall take additional samples in the Distribution System the following day at the locations required by 310 CMR 22.07E(7)(b)2.b. in addition to the sample required at the entrance to the Distribution System.

ii.Monthly Monitoring. Each Supplier of Water shall take a three-sample set each month in the Distribution System. The supplier shall take one sample at each of the following locations: near the first customer, at a location representative of average residence time, and at a location reflecting maximum residence time in the Distribution System. Any additional routine sampling shall be conducted in the same manner (as three-sample sets, at the specified locations). Each Supplier of Water may use the results of additional monitoring conducted under 310 CMR 22.07E(7)(b)2.b. to meet the requirement for monitoring in 310 CMR 22.07E(7)(b)2.a.ii.

b.Additional Monitoring. On each day following a routine sample monitoring result that exceeds the chlorite MCL at the entrance to the Distribution System, the Supplier of Water is required to take three chlorite Distribution System samples at the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the Distribution System as possible (reflecting maximum residence time in the Distribution System).

c.Reduced Monitoring.

i. Chlorite monitoring at the entrance to the Distribution System required by 310 CMR 22.07E(7)(b)2.a.i. may not be reduced.

ii. Chlorite monitoring in the Distribution System required by 310 CMR 22.07E(7)(b)2.a.ii. may be reduced to one three-sample set per quarter after one year of monitoring where no individual chlorite sample taken in the Distribution System under 310 CMR 22.07E(7)(b)2.a.ii. has exceeded the chlorite MCL and the supplier has not been required to conduct monitoring under 310 CMR 22.07E(7)(b)2.b. The supplier may remain on the reduced monitoring schedule until either any of the three individual chlorite samples taken quarterly in the Distribution System under 310 CMR 22.07E(b)2.a.ii. exceeds the chlorite MCL or the system is required to conduct monitoring under 310 CMR 22.07E(7)(b)2.b., at which time the supplier shall revert to routine monitoring.

3.Bromate.

a.Routine Monitoring. Community and Non-transient Non-community Water Systems using ozone, for Disinfection or oxidation, shall take one sample per month for each treatment plant in the system using ozone. Each Supplier of Water shall take samples monthly at the entrance to the Distribution System while the ozonation system is operating under normal conditions.

b.Reduced Monitoring.

i. Until March 31, 2009, each Supplier of Water who is required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system demonstrates that the average source water bromide concentration is less than 0.05 mg/l based upon representative monthly bromide measurements for one year. The Supplier of Water may remain on reduced bromate monitoring until the Running Annual Average source water bromide concentration, computed quarterly, is equal to or greater than 0.05 mg/l based upon representative monthly measurements. If the Running Annual Average source water bromide concentration is >=0.05 mg/l, the Supplier of Water shall resume routine monitoring required by 310 CMR 22.07E(7)(b)3.a. in the following month.

ii. Beginning April 1, 2009, each Supplier of Water may no longer use the provisions of 310 CMR 22.07E(7)(b)3.b.i. to qualify for reduced monitoring. A Supplier of Water required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system's Running Annual Average bromate concentration is 0.0025 mg/L based on monthly bromate measurements under 310 CMR 22.07E(7)(b)3.a. for the most recent four quarters, with samples analyzed using Method 302.0, 317.0 Revision 2.0, 326.0, 321.8 or 557. If a Supplier of Water has qualified for reduced bromate monitoring under 310 CMR 22.07E(7)(b)3.b.i. that Supplier of Water may remain on reduced monitoring as long as the Running Annual Average of quarterly bromate samples is 0.0025 mg/L based on samples analyzed using Method 302.0, 317.0 Revision 2.0, 326.0, 321.8 or 557. If the Running Annual Average bromate concentration is >0.0025 mg/L, the Supplier of Water must resume routine monitoring required by 310 CMR 22.07E(7)(b)3.a.

(c)Monitoring Requirements for Disinfectant Residuals.

1.Chlorine and Chloramines.

a.Routine Monitoring. Community and Non-transient Non-community Water Systems that use chlorine or chloramines shall measure the residual Disinfectant level in the Distribution System at the same point in the Distribution System and at the same time as total coliforms are sampled, as specified in 310 CMR 22.05. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water may use the results of Residual Disinfectant Concentration sampling conducted under 310 CMR 22.20A(5)(b)6. for unfiltered systems or 310 CMR 22.20A(5)(c)3. for systems which filter, in lieu of taking separate samples.

b.Reduced Monitoring. Monitoring may not be reduced.

2.Chlorine Dioxide.

a.Routine Monitoring. Community, Non-transient Non-community, and Transient Non-community Water Systems that use chlorine dioxide for Disinfection or oxidation shall take daily samples at the entrance to the Distribution System. For any daily sample that exceeds the MRDL, the supplier shall take samples in the Distribution System the following day at the locations required by 310 CMR 22.07E(7)(c)2.b., in addition to the sample required at the entrance to the Distribution System.

b.Additional Monitoring. On each day following a routine sample monitoring result that exceeds the MRDL, the supplier is required to take three chlorine dioxide Distribution System samples. If chlorine dioxide or chloramines are used to maintain a Disinfectant residual in the Distribution System, or if chlorine is used to maintain a Disinfectant residual in the Distribution System and there are no Disinfection addition points after the entrance to the Distribution System (i.e., no booster chlorination), the supplier shall take three samples as close to the first customer as possible, at intervals of at least six hours. If chlorine is used to maintain a Disinfectant residual in the Distribution System and there are one or more Disinfection addition points after the entrance to the Distribution System (i.e., booster chlorination), the supplier shall take one sample at each of the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the Distribution System as possible (reflecting maximum residence time in the Distribution System).

c.Reduced Monitoring. Chlorine dioxide monitoring may not be reduced.

(d)Monitoring Requirements for Disinfection Byproduct Precursors (DBPP).

1.Routine Monitoring. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water which use conventional Filtration treatment (as defined in 310 CMR 22.02) shall monitor each treatment plant for TOC no later than the point of combined filter effluent Turbidity monitoring and representative of the treated water. Each Supplier of Water required to monitor under 310 CMR 22.07E(7)(d)1. shall also monitor for TOC in the source water prior to any treatment at the same time as monitoring for TOC in the treated water. The source water TOC sample may be taken at an earlier time than the treated water TOC sample where the difference between the two sampling times is equal to the time it takes the water to pass through the treatment processes. These samples (source water and treated water) are referred to as paired samples. At the same time as the source water sample is taken, the Supplier of Water shall monitor for alkalinity in the source water prior to any treatment. Each Supplier of Water shall take one paired sample and one source water alkalinity sample per month per plant at a time representative of normal operating conditions and influent water quality.

2.Reduced Monitoring. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water with an average treated water TOC of less than 2.0 mg/l for two consecutive years, or less than 1.0 mg/l for one year, may reduce monitoring for both TOC and alkalinity to one paired sample and one source water alkalinity sample per plant per quarter. The Supplier of Water shall revert to routine monitoring in the month following the quarter when the annual average treated water TOC is > 2.0 mg/l.

(e)Bromide. Each Supplier of Water who is required to analyze for bromate may reduce bromate monitoring from monthly to once per quarter, if the Supplier of Water demonstrates that the average source water bromide concentration is > 0.05 mg/l based upon representative monthly measurements for one year. The Supplier of Water shall continue bromide monitoring to remain on reduced bromate monitoring.

(f)Monitoring Plans. Each Supplier of Water who is required to monitor under 310 CMR 22.07E shall develop and implement a monitoring plan. The Supplier of Water shall maintain the plan and make it available for inspection by the Department and the general public no later than 30 days following the applicable compliance dates in 310 CMR 22.07E(3). Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water that serves more than 3,300 people shall submit a copy of the monitoring plan to the Department no later than the date of the first report required under 310 CMR 22.07E(9). The Department may also require the plan to be submitted by any other supplier. After review, the Department may require changes in any plan elements. The plan shall include at least the following elements.

1. Specific locations and schedules for collecting samples for any parameters included in 310 CMR 22.07E(7).

2. How the system will calculate compliance with MCLs, MRDLs, and Treatment Techniques.

3. If approved for monitoring as a consecutive system, or if providing water to a consecutive system, under the provisions of 310 CMR 22.12, the sampling plan shall reflect the entire Distribution System.

4. Name, signature and title of system representative and date of signature.

5. System name and system PWSID No.

(8)Compliance Requirements.

(a)General Requirements.

1. Where compliance is based on a Running Annual Average of monthly or quarterly samples or averages and the system fails to monitor for TTHM, HAA5, or bromate, this failure to monitor will be treated as a monitoring violation for the entire period covered by the annual average. Where compliance is based on a Running Annual Average of monthly or quarterly samples or averages and the supplier's failure to monitor makes it impossible to determine compliance with MRDLs for chlorine and chloramines, this failure to monitor will be treated as a monitoring violation for the entire period covered by the annual average.

2. All samples taken and analyzed under the provisions of 310 CMR 22.07E shall be included in determining compliance, even if that number is greater than the minimum required.

3. If, during the first year of monitoring under 310 CMR 22.07E(7), any individual quarter's average will cause the Running Annual Average of that system to exceed the MCL for Total Trihalomethanes, Haloacetic Acids (Five), or bromate; or the MRDL for chlorine or chloramine, the system is out of compliance at the end of that quarter.

(b)Disinfection Byproducts.

1. TTHM and HAA5.

a. For each Supplier of Water monitoring quarterly, compliance with MCLs in 310 CMR 22.07E(1) shall be based on a running annual arithmetic average, computed quarterly, of quarterly arithmetic averages of all samples collected by the supplier as prescribed by 310 CMR 22.07E(7)(b)1.

b. For each Supplier of Water monitoring less frequently than quarterly, the supplier demonstrates MCL compliance if the average of samples taken that year under the provisions of 310 CMR 22.07E(7)(b)1. does not exceed the MCLs in 310 CMR 22.07E(1). If the average of these samples exceeds the MCL, the supplier shall increase monitoring to once per quarter per treatment plant and such a system is not in violation of the MCL until it has completed one year of quarterly monitoring, unless the result of fewer than four quarters of monitoring will cause the Running Annual Average to exceed the MCL, in which case the Supplier of Water is in violation at the end of that quarter. Each Supplier of Water who is required to increase monitoring frequency to quarterly monitoring shall calculate compliance by including the sample which triggered the increased monitoring plus the following three quarters of monitoring.

c. If the running annual arithmetic average of quarterly averages covering any consecutive four-quarter period exceeds the MCL, the Supplier of Water is in violation of the MCL and shall notify the public pursuant to 310 CMR 22.16, in addition to reporting to the Department pursuant to 310 CMR 22.07E(9).

d. If a Supplier of Water fails to complete four consecutive quarters of monitoring, compliance with the MCL for the last four-quarter Compliance Period shall be based on an average of the available data.

2.Bromate. Compliance shall be based on a running annual arithmetic average, computed quarterly, of monthly samples (or, for months in which the Supplier of Water takes more than one sample, the average of all samples taken during the month) collected by the Supplier of Water as prescribed by 310 CMR 22.07E(7)(b)3. If the average of samples covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and shall notify the public pursuant to 310 CMR 22.16, in addition to reporting to the Department pursuant to 310 CMR 22.07E(9). If a Supplier of Water fails to complete 12 consecutive months of monitoring, compliance with the MCL for the last four-quarter Compliance Period shall be based on an average of the available data.

3.Chlorite. Compliance shall be based on an arithmetic average of each three-sample set taken in the Distribution System as prescribed by 310 CMR 22.07E(7)(b)2.a.ii. and b. If the arithmetic average of any three-sample set exceeds the MCL, the supplier is in violation of the MCL and shall notify the public pursuant to 310 CMR 22.16, in addition to reporting to the Department pursuant to 310 CMR 22.07E(9).

(c)Disinfectant Residuals.

1.Chlorine and Chloramines.

a. Compliance shall be based on a running annual arithmetic average, computed quarterly, of monthly averages of all samples collected by the Supplier of Water under 310 CMR 22.07E(7)(c)1. If the average covering any consecutive four-quarter period exceeds the MRDL, the supplier is in violation of the MRDL and shall notify the public pursuant to 310 CMR 22.16, in addition to reporting to the Department pursuant to 310 CMR 22.07E(9).

b. In cases where the Supplier of Water switches between the use of chlorine and chloramines for residual Disinfection during the year, compliance shall be determined by including together all monitoring results of both chlorine and chloramines in calculating compliance. Reports submitted pursuant to 310 CMR 22.07E(9) shall clearly indicate which residual Disinfectant was analyzed for each sample.

2.Chlorine Dioxide.

a.Acute Violations. Compliance shall be based on consecutive daily samples collected by the system under 310 CMR 22.07E(7)(c)2. If any daily sample taken at the entrance to the Distribution System exceeds the MRDL, and on the following day one (or more) of the three samples taken in the Distribution System exceed the MRDL, the supplier is in violation of the MRDL and shall take immediate corrective action to lower the level of chlorine dioxide below the MRDL and shall notify the public pursuant to the procedures for acute health risks in 310 CMR 22.16 in addition to reporting to the Department pursuant to 310 CMR 22.07E(9). Failure to take samples in the Distribution System the day following an exceedance of the chlorine dioxide MRDL at the entrance to the Distribution System will also be considered an MRDL violation and the supplier shall notify the public of the violation in accordance with the provisions for acute violations under 310 CMR 22.16 in addition to reporting to the Department pursuant to 310 CMR 22.07E(9).

b.Nonacute Violations. Compliance shall be based on consecutive daily samples collected by the Supplier of Water under 310 CMR 22.07E(7)(c)2. If any two consecutive daily samples taken at the entrance to the Distribution System exceed the MRDL and all Distribution System samples taken are below the MRDL, the supplier is in violation of the MRDL and shall take corrective action to lower the level of chlorine dioxide below the MRDL at the point of sampling and will notify the public pursuant to the procedures for nonacute health risks in 310 CMR 22.16 in addition to reporting to the Department pursuant to 310 CMR 22.07E(9). Failure to monitor at the entrance to the Distribution System the day following an exceedance of the chlorine dioxide MRDL at the entrance to the Distribution System is also an MRDL violation and the supplier shall notify the public of the violation in accordance with the provisions for nonacute violations under 310 CMR 22.16 in addition to reporting to the Department pursuant to 310 CMR 22.07E(9).

(d)Disinfection Byproduct Precursors (DBPP). Compliance shall be determined as specified by 310 CMR 22.07E(10)(c). Each Supplier of Water may begin monitoring to determine whether Step 1 TOC removals can be met 12 months prior to the compliance date for the system. This monitoring is not required and failure to monitor during this period is not a violation. However, any Supplier of Water who does not monitor during this period, and then determines in the first 12 months after the compliance date that they are not able to meet the Step 1 requirements in 310 CMR 22.07E(10)(b)2. and shall therefore apply for alternate minimum TOC removal (Step 2) requirements, are not eligible for retroactive approval of alternate minimum TOC removal (Step 2) requirements as allowed pursuant to 310 CMR 22.07E(10)(b)3. and are in violation. A Supplier of Water may apply for alternate minimum TOC removal (Step 2) requirements any time after the compliance date. For each suppliers of water who is required to meet Step 1 TOC removals, if the value calculated under 310 CMR 22.07E(10)(c)1.d. is less than 1.00, the system is in violation of the Treatment Technique requirements and shall notify the public pursuant to 310 CMR 22.16, in addition to reporting to the Department pursuant to 310 CMR 22.07E(9).

(9)Reporting and Recordkeeping Requirements.

(a) Each Supplier of Water who is required to sample quarterly or more frequently shall report to the Department within ten days after the end of each quarter in which samples were collected, notwithstanding the provisions of 310 CMR 22.15. Each Supplier of Water who is required to sample less frequently than quarterly shall report to the Department within ten days after the end of each monitoring period in which samples were collected.

(b)Disinfection Byproducts. Each Supplier of Water shall report the information specified in the following table:

If you are a...	You shall report...¹
1. System monitoring for TTHM and HAA5 under the requirements of 310 CMR 22.07E(7)(b) on a quarterly or more frequent basis.	a. The number of samples taken during the last quarter. b. The location, date, and result of each sample taken during the last quarter. c. The arithmetic average of all samples taken in the last quarter. d. The annual arithmetic average of the quarterly arithmetic averages of 310 CMR 22.07(9)(b)1.c. for the last four quarters. e. Whether, based on 310 CMR 22.07E(8)(b)1., the MCL was violated.
2. System monitoring for TTHM and HAA5 under the requirements of 310 CMR 22.07E(7)(b) less frequently than quarterly (but at least annually).	a. The number of samples taken during the last year. b. The location, date, and result of each sample taken during the last monitoring period. c. The arithmetic average of all samples taken over the last year. d. Whether, based on 310 CMR 22.07E(8)(b)1., the MCL was violated.
3. System monitoring for TTHM and HAA5 under the requirements of 310 CMR 22.07E(7)(b) less frequently than annually.	a. The location, date, and result of the last sample taken. b. Whether, based on 310 CMR 22.07E(8)(b)1., the MCL was violated.
4. System monitoring for chlorite under the requirements of 310 CMR 22.07E(7)(b)	a. The number of entry point samples taken each month for the last three months. b. The location, date, and result of each sample (both entry point and Distribution System) taken during the last quarter. c. For each month in the reporting period, the arithmetic average of all samples taken in each three sample set taken in the Distribution System. d. Whether, based on 310 CMR 22.07E(8)(b)3., the MCL was violated, in which month, and how many times it was violated each month.
5. System monitoring for bromate under the requirements of 310 CMR 22.07E(7)(b).	a. The number of samples taken during the last quarter. b. The location, date, and result of each sample taken during the last quarter. c. The arithmetic average of the monthly arithmetic averages of all samples taken in the last year. d. Whether, based on 310 CMR 22.07E(8)(b)2., the MCL was violated.

¹ The Department may choose to perform calculations and determine whether the MCL was violated.

(c)Disinfectants. Each Supplier of Water shall report the information specified in the following table:

If you are a...

You shall report...¹

1. System monitoring for chlorine or chloramines under the requirements of 310 CMR 22.07E(7)(c).

a. The number of samples taken during each month of the last quarter.

b. The monthly arithmetic average of all samples taken in each month for the last 12 months.

c. The arithmetic average of the monthly averages for the last 12 months.

d. Whether, based on 310 CMR 22.07E(8)(c)1., the MRDL was violated.

2. System monitoring for chlorine dioxide under the requirements of 310 CMR 22.07E(7)(c).

a. The dates, results, and locations of samples taken during the last quarter.

b. Whether, based on 310 CMR 22.07E(8)(c)2., the MRDL was violated.

c. Whether the MRDL was exceeded in any two consecutive daily samples and whether the resulting violation was acute or nonacute.

¹ The Department may choose to perform calculations and determine whether the MRDL was exceeded or violated.

(d)Disinfection Byproduct Precursors and Enhanced Coagulation or Enhanced Softening. Each Supplier of Water shall report the information specified in the following table:

If you are a . . .

You shall report . . .¹

1. System monitoring monthly or quarterly for TOC under the requirements of 310 CMR 22.07E(7)(d) and required to meet the Enhanced Coagulation or Enhanced Softening requirements in 310 CMR 22.07E(10)(b)2. or (b)3.

a. The number of paired (source water and treated water) samples taken during the last quarter.

b. The location, date, and result of each paired sample and associated alkalinity taken during the last quarter.

c. For each month in the reporting period that paired samples were taken, the arithmetic average of the percent reduction of TOC for each paired sample and the required TOC percent removal.

d. Calculations for determining compliance with the TOC percent removal requirements, as provided in 310 CMR 22.07E(10)(c)1.

e. Whether the system is in compliance with the Enhanced Coagulation or Enhanced Softening percent removal requirements in 310 CMR 22.07E(10)(b) for the last four quarters.

¹ The Department may choose to perform calculations and determine whether the Treatment Technique was met.

If you are a . . .

You shall report . . .¹

2. System monitoring monthly or quarterly for TOC under the requirements of Sec. 310 CMR 22.07E(7)(d) and meeting one or more of the alternative compliance criteria in 310 CMR 22.07E(10)(a)2. or (a)3.

a. The alternative compliance criterion that the system is using.

b. The number of paired samples taken during the last quarter.

c. The location, date, and result of each paired sample and associated alkalinity taken during the last quarter.

d. The running annual arithmetic average based on monthly averages (or quarterly samples) of source water TOC for systems meeting a criterion in 310 CMR 22.07E(10)(a)2.a. or (a)2.c. or of treated water TOC for systems meeting the criterion in 310 CMR 22.07E(10)(a)2.b.

e. The running annual arithmetic average based on monthly averages (or quarterly samples) of source water SUVA for systems meeting the criterion in 310 CMR 22.07E(10)(a)2.e. or of treated water SUVA for systems meeting the criterion in 310 CMR 22.07E(10)(a)2.f.

f. The Running Annual Average of source water alkalinity for systems meeting the criterion in 310 CMR 22.07E(10)(a)2.c. and of treated water alkalinity for systems meeting the criterion in 310 CMR 22.07E(10)(a)3.a.

g. The Running Annual Average for both TTHM and HAA5 for systems meeting the criterion in 310 CMR 22.07E(10)(a)2.c. or (a)2.d.

h. The Running Annual Average of the amount of magnesium hardness removal (as CaCO₃, in mg/l) for systems meeting the criterion in 310 CMR 22.07E(10)(a)3.b.

i. Whether the system is in compliance with the particular alternative compliance criterion in 310 CMR 22.07E(10)(a)2. or (a)3.

¹ The Department may choose to perform calculations and determine whether the Treatment Technique was met.

(10)Treatment Technique for Control of Disinfection Byproduct (DBP) Precursors.

(a)Applicability.

1. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water using conventional Filtration treatment (as defined in 310 CMR 22.02) shall operate with Enhanced Coagulation or Enhanced Softening to achieve the TOC percent removal levels specified in 310 CMR 22.07E(10)(b) unless the supplier meets at least one of the alternative compliance criteria listed in 310 CMR 22.07E(10)(a)2. or 3.

2.Alternative Compliance Criteria for Enhanced Coagulation and Enhanced Softening Systems. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water using conventional Filtration treatment may use the alternative compliance criteria in 310 CMR 22.07E(10)(a)2.a. through f. to comply with 310 CMR 22.07E(10) in lieu of complying with 310 CMR 22.07E(10)(b). Each Supplier of Water shall still comply with monitoring requirements in 310 CMR 22.07E(7)(d).

a. The supplier's source water TOC level, measured according to 310 CMR 22.07E(6)(e)3., is less than 2.0 mg/l, calculated quarterly as a Running Annual Average.

b. The supplier's treated water TOC level, measured according to 310 CMR 22.07E(6)(e)3., is less than 2.0 mg/l, calculated quarterly as a Running Annual Average.

c. The supplier's source water TOC level, measured according to 310 CMR 22.07E(6)(e)3., is less than 4.0 mg/l, calculated quarterly as a Running Annual Average; the source water alkalinity, measured according to 310 CMR 22.07E(6)(e)1., is greater than 60 mg/l (as CaCO₃), calculated quarterly as a Running Annual Average; and either the TTHM and HAA5 Running Annual Averages are no greater than 0.040 mg/l and 0.030 mg/l, respectively; or prior to the effective date for compliance in 310 CMR 22.07E(3), the supplier has made a clear and irrevocable financial commitment not later than the effective date for compliance in 310 CMR 22.07E(3), to use technologies that will limit the levels of TTHM and HAA5 to no more than 0.040 mg/l and 0.030 mg/l, respectively. The Supplier of Water shall submit evidence of a clear and irrevocable financial commitment, in addition to a schedule containing milestones and periodic progress reports for installation and operation of appropriate technologies, to the Department for approval not later than the effective date for compliance in 310 CMR 22.07E(3). These technologies shall be installed and operating not later than June 30, 2005. Failure to install and operate these technologies by the date in the approved schedule will constitute a violation of 310 CMR 22.00.

d. The TTHM and HAA5 Running Annual Averages are no greater than 0.040 mg/l and 0.030 mg/l, respectively, and the system uses only chlorine for primary Disinfection and maintenance of a residual in the Distribution System.

e. The supplier's source water SUVA, prior to any treatment and measured monthly according to 310 CMR 22.07E(6)(e)4., is less than or equal to 2.0 l/mg-m, calculated quarterly as a Running Annual Average.

f. The supplier's finished water SUVA, measured monthly according to 310 CMR 22.07E(6)(e)4., is less than or equal to 2.0 l/mg-m, calculated quarterly as a Running Annual Average.

3.Additional Alternative Compliance Criteria for Enhanced Softening Systems. Each Supplier of Water who practices Enhanced Softening who cannot achieve the TOC removals required by 310 CMR 22.07E(10)(b)2. may use the alternative compliance criteria in 310 CMR 22.07E(10)(a)3.a. and b. in lieu of complying with 310 CMR 22.07E(10)(b). Each Supplier of Water shall still comply with monitoring requirements in 310 CMR 22.07E(7)(d).

a. Softening that results in lowering the treated water alkalinity to less than 60 mg/l (as CaCO₃), measured monthly according to 310 CMR 22.07E(6)(e)1. and calculated quarterly as a Running Annual Average.

b. Softening that results in removing at least 10 mg/l of magnesium hardness (as CaCO₃), measured monthly according to 310 CMR 22.07E(6)(e)6. and calculated quarterly as an annual running average.

(b)Enhanced Coagulation and Enhanced Softening Performance Requirements.

1. Each Supplier of Water shall achieve the percent reduction of TOC specified in 310 CMR 22.07E(10)(b)2. between the source water and the combined filter effluent, unless the Department approves the supplier's request for alternate minimum TOC removal (Step 2) requirements under 310 CMR 22.07E(10)(b)3.

2. Required Step 1 TOC reductions, indicated in the following table, are based upon specified source water parameters measured in accordance with 310 CMR 22.07E(6)(e). Each Supplier of Water who practices softening is required to meet the Step 1 TOC reductions in the far-right column (Source water alkalinity >120 mg/l) for the specified source water TOC:

Step 1 Required Removal of TOC by Enhanced Coagulation and Enhanced Softening for Systems Using Surface Water or Groundwater Under the Direct Influence of Surface Water and Using Conventional Treatment^1,2
Source-water TOC, mg/l	Source-water alkalinity, mg/l as CaCO₃
Source-water TOC, mg/l	0-60	> 60-120	> 120³
>2.0-4.0	35.0 %	25.0 %	15.0 %
>4.0-8.0	45.0 %	35.0 %	25.0 %
>8.0	50.0 %	40.0 %	30.0 %

¹ Systems meeting at least one of the conditions in 310 CMR 22.07E(10)(a)2. are not required to operate with Enhanced Coagulation.

² Softening systems meeting one of the alternative compliance criteria in 310 CMR 22.07E(10)(a)3. are not required to operate with Enhanced Softening.

³ Systems practicing softening shall meet the TOC removal requirements in this column.

3. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water using conventional treatment that cannot achieve the Step 1 TOC removals required by 310 CMR 22.07E(10)(b)2. due to water quality parameters or operational constraints shall apply to the Department, within three months of failure to achieve the TOC removals required by 310 CMR 22.07E(10)(b)2., for approval of alternative minimum TOC (Step 2) removal requirements. If the Department approves the alternative minimum TOC removal (Step 2) requirements, the Department may make those requirements retroactive for the purposes of determining compliance. Until the Department approves the alternate minimum TOC removal (Step 2) requirements, the supplier shall meet the Step 1 TOC removals contained in 310 CMR 22.07E(10)(b)2.

4.Alternate Minimum TOC Removal (Step 2) Requirements. Applications made to the Department by a Supplier of Water who practices Enhanced Coagulation for approval of alternate minimum TOC removal (Step 2) requirements under 310 CMR 22.07E(10)(b)3. shall include, at a minimum, results of bench- or pilot-scale testing conducted under 310 CMR 22.07E(10)(b)4.a. The submitted bench- or pilot-scale testing shall be used to determine the alternate Enhanced Coagulation level.

a. Alternate Enhanced Coagulation level is defined as Coagulation at a coagulant dose and pH as determined by the method described in 310 CMR 22.07E(10)(b)4.a. through e. such that an incremental addition of 10 mg/l of alum (or an equivalent amount of ferric salt) results in a TOC removal of 0.3 mg/l. The percent removal of TOC at this point on the "TOC removal versus coagulant dose"' curve is then defined as the minimum TOC removal required for the system. After the Department approves this minimum requirement, it shall supersede the minimum TOC removal, which is required by the table in 310 CMR 22.07E(10)(b)2. This minimum requirement will be effective until such time as the Department approves a new value based on the results of a new bench- and pilot-scale test. Failure to achieve Department-set alternative minimum TOC removal levels is a violation of 310 MR 22.00.

b. The Supplier of Water shall conduct bench- or pilot-scale testing of Enhanced Coagulation using representative water samples and adding ten mg/l increments of alum (or equivalent amounts of ferric salt) until the pH is reduced to a level less than or equal to the Enhanced Coagulation Step 2 target pH shown in the following table:

Enhanced Coagulation Step 2 Target pH
Alkalinity (mg/l as CaCO₃)	Target pH
0-60	5.5
>60-120	6.3
>120-240	7.0
>240	7.5

c. For waters with alkalinities of less than 60 mg/l for which addition of small amounts of alum coagulant (or the equivalent addition of ferric salts) drives the pH below 5.5 before significant TOC removal occurs, the Supplier of Water shall add chemicals necessary to maintain the pH between 5.3 and 5.7 in samples until the TOC removal of 0.3 mg/l per 10 mg/l alum added (or an equivalent amount of ferric salt) is reached.

d. The Supplier of Water may operate the system at any coagulant dose or pH necessary (consistent with 310 CMR 22.00 requirements) to achieve the minimum TOC percent removal approved under 310 CMR 22.07E(10)(b)3.

e. If the TOC removal is consistently less than 0.3 mg/l of TOC per ten mg/l of incremental alum dose at all dosages of alum (or equivalent doses of ferric salt), the water will be deemed to contain TOC not amenable to Enhanced Coagulation. The Supplier of Water may then apply to the Department for a waiver of Enhanced Coagulation requirements.

(c)Compliance Calculations.

1. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water other than those identified in 310 CMR 22.07E(10)(a)2. or 3. shall comply with requirements contained in 310 CMR 22.07E(10)(b)2. or 3. Each Supplier of Water shall calculate compliance quarterly, beginning after the system has collected 12 months of data, by determining an annual average using the following method:

a. Determine actual monthly TOC percent removal, equal to: (1-(treated water TOC/source water TOC)) x 100

b. Determine the required monthly TOC percent removal (from either the table in 310 CMR 22.07E(10)(b)2. or 3.).

c. Divide the value in 310 CMR 22.07E(10)(c)1.a. by the value in 310 CMR 22.07E(10)(c)1.b.

d. Add together the results of 310 CMR 22.07E(10)(c)1.c. for the last 12 months and divide by 12.

e. If the value calculated in 310 CMR 22.07E(10)(c)1.d. is less than 1.00, the supplier is not in compliance with the TOC percent removal requirements.

2. Each Supplier of Water may use the provisions in 310 CMR 22.07E(10)(c)2.a. through e. in lieu of the calculations in 310 CMR 22.07E(10)(c)1.a. through e to determine compliance with TOC percent removal requirements.

a. In any month that the Supplier of Water's treated or source water TOC level, measured according to 310 CMR 22.07E(6)(e)3., is less than 2.0 mg/l, the supplier may assign a monthly value of 1.0 (in lieu of the value calculated in 310 CMR 22.07E(10)(c)1.c.) when calculating compliance under the provisions of 310 CMR 22.07E(10)(c)1.

b. In any month that a Supplier of Water practicing softening removes at least 10 mg/l of magnesium hardness (as CaCO₃), the supplier may assign a monthly value of 1.0 (in lieu of the value calculated in 310 CMR 22.07E(10)(c)1.c.) when calculating compliance under the provisions of 310 CMR 22.07E(10)(c)1.

c. In any month that the supplier's source water SUVA, prior to any treatment and measured according to 310 CMR 22.07E(6)(e)4., is <= 2.0 l/mg-m, the supplier may assign a monthly value of 1.0 (in lieu of the value calculated in 310 CMR 22.07E(10)(c)1.c.) when calculating compliance under the provisions of 310 CMR 22.07E(10)(c)1.

d. In any month that the Supplier of Water's finished water SUVA, measured according to 310 CMR 22.07E(6)(e)4., is <= 2.0 l/mg-m, the supplier may assign a monthly value of 1.0 (in lieu of the value calculated in 310 CMR 22.07E(10)(c)1.c.) when calculating compliance under the provisions of 310 CMR 22.07E(10)(c)1.

e. In any month that a Supplier of Water practicing Enhanced Softening lowers alkalinity below 60 mg/l (as CaCO₃), the supplier may assign a monthly value of 1.0 (in lieu of the value calculated in 310 CMR 22.07E(10)(c)1.c.) when calculating compliance under the provisions of 310 CMR 22.07E(10)(c)1.

3. Each Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water using conventional treatment may also comply with the requirements of 310 CMR 22.07E(10) by meeting the criteria in 310 CMR 22.07E(10)(a)2. or 3.

(d)Treatment Technique Requirements for DBP Precursors. The EPA Administrator identifies the following as Treatment Techniques to control the level of Disinfection byproduct precursors in drinking water treatment and Distribution Systems: For a Supplier of Water who uses a Surface Water Source or groundwater source under the direct influence of surface water that uses conventional treatment, Enhanced Coagulation or Enhanced Softening.

310 CMR, § 22.07E

Amended by Mass Register Issue 1309, eff. 3/25/2016.

Amended by Mass Register Issue 1419, eff. 6/12/2020.