Cal. CIV § 8124

A claimant’s waiver and release does not release the owner, construction lender, or surety on a payment bond from a lien or claim unless both of the following conditions are satisfied: (a) The waiver and release is in substantially the form provided in this article and is signed by the claimant. (b) If the release is a conditional release, there is evidence of payment to the claimant. Evidence of payment may be either of the following: (1) The claimant’s endorsement on a single or joint payee check that has been paid by the financial institution on which it was drawn. (2) Written acknowledgment of payment by the claimant.