Cal. Civ. Code § 942

In order to make a claim for violation of the standards set forth in Chapter 2 (commencing with Section 896), a homeowner need only demonstrate, in accordance with the applicable evidentiary standard, that the home does not meet the applicable standard, subject to the affirmative defenses set forth in Section 945.5. No further showing of causation or damages is required to meet the burden of proof regarding a violation of a standard set forth in Chapter 2 (commencing with Section 896), provided that the violation arises out of, pertains to, or is related to, the original construction.