Meter Condition. Before a meter may be installed for revenue billing purposes the utility shall inspect and test the meter, and adjust it if necessary, so that its proof is within the tolerances specified in Regulation .02. Sample Testing New Meters. New meters may be sample tested for proof in accordance with a utility's sample plan of testing acceptable to the Commission. Leak Test. The meter may not leak when subjected to pressure and checked for leaks by: Immersion; Soap test; or A pressure drop test of a type acceptable to the Commission. Tinned Steel Case Meters. Each meter shall be subjected to an internal pressure of at least 2 psig when testing for leaks. Iron or Aluminum Case Meters. Iron or aluminum case meters shall be tested at a pressure at least 50 percent above operating pressure. The meters may be sample tested in accordance with the plan described in §B. If one or more meters in the sample is found to leak, additional testing shall be done as described in §B. Commission Test. A representative of the Commission will check the condition of meters in the meter shop of the utility from time to time by testing random samples of meters ready for installation. Re-test. When any meter is inactive, whether installed in service or not, for a period of 2 years or longer, it shall be tested, and adjusted if necessary before being placed in service again.