California Code, Public Utilities Code - PUC § 739.11

(a) For bills issued to customers of gas corporations and electrical corporations in which usage is estimated, it is the intent of the Legislature that, to the extent practicable, the methodology for estimation be simple, transparent, and cost effective to the customer, and produce reasonably accurate results.

(b) For each gas corporation and electrical corporation that, for some portion of residential customers, employs every-other-month meter reading and estimates bills for months when the customer's meter is not read, the commission shall direct the gas corporation or electrical corporation to include in its tariffs the methodology it employs to estimate bills for those months during which the meter is not read.