Cal. PCC § 10262.5

(a) Notwithstanding any other law, a prime contractor or subcontractor shall pay to any subcontractor, not later than seven days after receipt of each progress payment, the respective amounts allowed the contractor on account of the work performed by the subcontractors, to the extent of each subcontractor’s interest therein. In the event that there is a good faith dispute over all or any portion of the amount due on a progress payment from the prime contractor or subcontractor to a subcontractor, then the prime contractor or subcontractor may withhold no more than 150 percent of the disputed amount.

Any contractor who violates this section shall pay to the subcontractor a penalty of 2 percent of the amount due per month for every month that payment is not made. In any action for the collection of funds wrongfully withheld, the prevailing party shall be entitled to his or her attorney’s fees and costs.

(b) This section shall not be construed to limit or impair any contractual, administrative, or judicial remedies otherwise available to a contractor or a subcontractor in the event of a dispute involving late payment or nonpayment by a contractor or deficient subcontract performance or nonperformance by a subcontractor.

(c) On or before September 1 of each year, the head of each state agency shall submit to the Legislature a report on the number and dollar volume of written complaints received from subcontractors and prime contractors on contracts in excess of three hundred thousand dollars ($300,000), relating to violations of this section.