Cal. PCC § 10853

(a) If the trustees fail to make a progress payment on a contract within 39 days after receipt of an undisputed and properly submitted payment request from a contractor on a construction contract, the trustees shall pay interest to the contractor equivalent to the legal rate set forth in subdivision (a) of Section 685.010 of the Code of Civil Procedure. If the payment is not made within 39 days of receipt of the contractor’s request, and the Controller has processed the payment within 14 days of the receipt of the request, the trustees shall pay interest to the contractor equivalent to the legal rate as provided in subdivision (a) of Section 685.010 of the Code of Civil Procedure. If the payment is not made within 39 days of receipt of the contractor’s request, and the trustees have processed the payment within 25 days after the receipt of the request, the Controller shall pay interest equivalent to the legal rate as provided in subdivision (a) of Section 685.010 of the Code of Civil Procedure.

(b) Upon receipt of a payment request, the trustees shall act in accordance with the following:

(1) Each payment request shall be reviewed by the trustees as soon as practicable after receipt for the purpose of determining that the payment request is a proper payment request.

(2) Any payment request determined not to be a proper request suitable for payment shall be returned to the contractor as soon as practicable, but not later than seven days after receipt. A request returned pursuant to this paragraph shall be accompanied by a document setting forth in writing the reasons why the payment request is not proper.

(3) Upon request from the trustees, the Controller may elect to expedite each payment request and may charge the trustees an appropriate amount, as determined by the Controller, for costs incurred in expediting the payment request.

(c) The number of days available to the trustees to make a payment without incurring interest shall be reduced by the number of days by which the trustees exceed the seven-day return requirement set forth in paragraph (2) of subdivision (b).

(d) A properly submitted payment request shall be defined as the date upon which the trustees receive a payment request, certified in accordance with the contract, at the address identified in the contract.

(e) For purposes of this section:

(1) A “progress payment” includes all payments due contractors, except that portion of the final payment withheld pursuant to Section 10851.

(2) A payment request shall be considered properly executed if funds are available for payment of the payment request and payment is not delayed due to an audit inquiry by the Controller.