(1) Electric utilities must include in their tariffs a statement describing their practices under these rules covering:

(a) A description of methods used and frequency of tests for determining electric meter accuracy. The description must include, but is not limited to:

(i) Test group detail and selection procedures;

(ii) Performance standard details for meters that exceed the maximum allowable tolerance for slow as well as fast meters;

(iii) The corrective action and time period in which such action will be implemented; and

(iv) Reference to an industry standard such as ANSI C12.1 or ANSI/[isrt]ASQC-Z1.9 that will establish acceptable criteria for numerical analysis. Information about the ANSI C12.1 regarding the version adopted and where to obtain it is set out in WAC 480-100-999, Adoption by reference.

(b) A description of meter testing equipment, including methods employed to ascertain and maintain accuracy of all testing equipment.

(c) If an electric utility does not maintain meter testing equipment, the electric utility must state that it will use a qualified testing laboratory for this purpose. The utility must notify the commission by separate correspondence of the name of the testing laboratory making meter tests if it does not maintain meter testing equipment.

(d) The testing and adjustment program used for meters prior to installation and periodically after installation, if applicable.

(2) If an electric utility changes any portion of its meter test procedures after they have been approved by the commission, the utility must submit a revised tariff.