California Code, Civil Code - CIV § 9406

(a) A claimant that contests the direct contractor's affidavit shall serve on the public entity a counteraffidavit alleging the details of the claim and describing the specific basis on which the claimant contests or rebuts the allegations of the contractor's affidavit. The counteraffidavit shall be served within the time stated in the public entity's notice, together with proof of service of a copy of the counteraffidavit on the direct contractor. The service of the counteraffidavit on the public entity and the copy of the affidavit on the direct contractor shall comply with the requirements of Chapter 2 (commencing with Section 8100) of Title 1.

(b) If no counteraffidavit with proof of service is served on the public entity within the time stated in the public entity's notice, the public entity shall immediately release the funds, or the portion of the funds demanded by the affidavit, without further notice to the claimant, and the public entity is not liable in any manner for their release.

(c) The public entity is not responsible for the validity of an affidavit or counteraffidavit under this article.