Sec. 42.
(a) Systems shall complete the applicable source water monitoring and treatment requirements (described in the referenced portions of subsection (b) and in sections 37 and 39 of this rule) by the following deadlines: STEP ONE: A system exceeding the lead or copper action level shall: (A) complete lead and copper source water monitoring (as required by section 39(b) of this rule); and(B) make a treatment recommendation to the commissioner (as required by subsection (b)(1)); not later than one hundred eighty (180) days after the end of the monitoring period during which the lead or copper action level was exceeded.
STEP TWO: The commissioner shall make a determination regarding source water treatment (as required by subsection (b)(2))
within six (6) months after submission of monitoring results under STEP ONE.
STEP THREE: If the commissioner requires installation of source water treatment, the system shall install the treatment (as required by subsection (b)(3)) within twenty-four (24) months after completion of STEP TWO.
STEP FOUR: The system shall complete follow-up:
(A) tap water monitoring (as required by section 37(d)(2) of this rule); and(B) source water monitoring (as required by section 39(c) of this rule); within thirty-six (36) months after completion of STEP TWO. STEP FIVE: The commissioner shall:
(A) review the system's installation and operation of source water treatment; and(B) specify maximum permissible source water levels (as required by subsection (b)(4)); within six (6) months after completion of STEP FOUR. STEP SIX: The system shall:
(A) operate in compliance with the maximum permissible lead and copper source water levels (as required by subsection (b)(4)) specified by the commissioner; and(B) continue source water monitoring (as required by section 39(d) of this rule).