CA Gov't Code Section 20538

(a)

All amounts due to the retirement system by a contracting agency under this part shall be paid through an electronic funds transfer method prescribed by the board. This payment requirement is effective upon declaration by the board.

(b)

A contracting agency that is unable, for good cause, to comply with subdivision (a), may apply to the board for a waiver that allows the agency to pay in an alternate manner as prescribed by the board, but not by credit card payment.