California Code, Health and Safety Code - HSC § 25403.6

(a) Except as provided in Section 25403.4, notwithstanding any other state law or policy, a local agency that undertakes and completes a cleanup, or otherwise causes a cleanup to be undertaken and completed pursuant to this chapter shall not be liable based on its ownership of property after a release occurred, for any costs that any responsible party for that release incurs to investigate or clean up the release or to compensate others for the effects of that release.

(b) Except as provided in Section 25403. 2,  1 this article does not limit the powers of the state board or a regional board to enforce Division 7 (commencing with Section 13000) of the Water Code.