California Code, Civil Code - CIV § 9502

(a) The claimant shall commence an action against the public entity and the direct contractor to enforce payment of the claim stated in a stop payment notice at any time after 10 days from the date the claimant gives the stop payment notice.

(b) The claimant shall commence an action against the public entity and the direct contractor to enforce payment of the claim stated in a stop payment notice not later than 90 days after expiration of the time within which a stop payment notice must be given.

(c) An action under this section may not be brought to trial or judgment entered before expiration of the time provided in subdivision (b).

(d) If a claimant does not commence an action to enforce payment of the claim stated in a stop payment notice within the time provided in subdivision (b), the notice ceases to be effective and the public entity shall release funds withheld pursuant to the notice.