Cal. CIV § 8812

(a) If an owner withholds a retention from a direct contractor, the owner shall, within 45 days after completion of the work of improvement, pay the retention to the contractor. (b) If part of a work of improvement ultimately will become the property of a public entity, the owner may condition payment of a retention allocable to that part on acceptance of the part by the public entity. (c) If there is a good faith dispute between the owner and direct contractor as to a retention payment due, the owner may withhold from final payment an amount not in excess of 150 percent of the disputed amount.