D.C. Mun. Regs. tit. 15, r. 15-2351
A representative of the Commission shall check the condition of meters in the meter shop of the gas corporation from time to time by testing random samples of meters ready for installation.
When any meter is inactive, whether installed in service or not, for a period of two (2) years or longer, it shall be tested, and adjusted if necessary, before being placed in service again.
Meters shall measure cubic feet of gas and bills rendered for gas service, shall contain the readings of the meter at the beginning and ending dates of the billing period and shall state clearly that the bill is based upon actual meter readings by the gas corporation, a customer reading, or an estimate of usage.
Care shall be exercised in the use and handling of test equipment to assure that the accuracy is not impaired.
Each natural gas corporation which corrects meter readings to compensate for pressure shall have dead weight testers, test quality precision type bourdon tube spring gauges, mercury manometers, or field type dead weight pressure gauges as necessary for the proper testing of the pressure correcting devices.
Each gas corporation shall maintain a proper record of the factor(s) used in compensating for pressure and temperature and the basis for computing such factor(s).
Upon request, the gas corporation shall provide a record of the factor(s) and the basis for computing the factor(s) to the Commission's Office of Engineering.
If these factor(s) are revised, the gas corporation shall immediately inform the Office of Engineering of these changes, in writing, and shall provide the basis for these changes.
Each gas corporation which corrects meter readings to compensate for temperature shall have accurate meters and other equipment as necessary for the proper testing of the temperature correcting devices.
Meters to be tested shall be stored in a manner that the temperature of the meters is substantially the same as the temperature of the prover.
D.C. Mun. Regs. tit. 15, r. 15-2351