Cal. Civil Code § 910

Prior to filing an action against any party alleged to have contributed to a violation of the standards set forth in Chapter 2 (commencing with Section 896), the claimant shall initiate the following prelitigation procedures: (a) The claimant or his or her legal representative shall provide written notice via certified mail, overnight mail, or personal delivery to the builder, in the manner prescribed in this section, of the claimant’s claim that the construction of his or her residence violates any of the standards set forth in Chapter 2 (commencing with Section 896). That notice shall provide the claimant’s name, address, and preferred method of contact, and shall state that the claimant alleges a violation pursuant to this part against the builder, and shall describe the claim in reasonable detail sufficient to determine the nature and location, to the extent known, of the claimed violation. In the case of a group of homeowners or an association, the notice may identify the claimants solely by address or other description sufficient to apprise the builder of the locations of the subject residences. That document shall have the same force and effect as a notice of commencement of a legal proceeding. (b) The notice requirements of this section do not preclude a homeowner from seeking redress through any applicable normal customer service procedure as set forth in any contractual, warranty, or other builder-generated document; and, if a homeowner seeks to do so, that request shall not satisfy the notice requirements of this section.