Cal. PUC § 755

(a) It is the intent of the Legislature that:

(1) An electrical, gas, or water corporation that offers customers credit card or debit card payment options, may recover the reasonable expenses incurred by the electrical, gas, or water corporation for providing the customers the option of paying their bills by credit card or debit card.

(2) Only the customers that choose to use these payment options incur the additional charge and that no portion of the expense is shifted to customers that do not choose to pay a bill by credit card or debit card, unless and until the commission determines that the savings to ratepayers exceeds the net cost of accepting those cards.

(3) The acceptance of credit cards or debit cards neither increases nor decreases the profitability of the electrical, gas, or water corporation.

(b) An electrical, gas, or water corporation may offer credit card and debit card bill payment options, if approved by the commission. The electrical, gas, or water corporation may recover reasonable transaction costs incurred by the electrical, gas, or water corporation only from those customers that choose to pay by those payment options.

(c) The commission shall determine through existing regulatory mechanisms the reasonableness of transaction costs charged to customers that choose to pay an electrical, gas, or water corporation by a credit card or debit card bill payment option pursuant to this section. The commission shall determine how any associated costs or potential savings as a result of those customers paying by the credit card or debit card payment option shall be passed on to electrical, gas, or water corporation customers. In determining how these savings or costs are passed on to customers, the commission shall do the following:

(1) The transaction costs that are passed on to customers pursuant to subdivision (b) shall be offset by any savings in transaction costs the electrical, gas, or water corporation derives as a result of those customers paying by credit card and debit card.

(2) If the commission determines that the use of credit cards and debit cards results in no net cost to the electrical, gas, or water corporation, there shall be no individual customer transaction fee as provided for in subdivision (b).

(3) If the commission determines that the savings to the electrical, gas, or water corporation exceeds the costs to the electrical, gas, or water corporation, the net savings shall be passed on to electrical, gas, or water corporation customers.