Cal. Civ. Code § 1102.5

If information disclosed in accordance with this article is subsequently rendered inaccurate as a result of any act, occurrence, or agreement subsequent to the delivery of the required disclosures, the inaccuracy resulting therefrom does not constitute a violation of this article. If at the time the disclosures are required to be made, an item of information required to be disclosed is unknown or not available to the transferor, and the transferor or his or her agent has made a reasonable effort to ascertain it, the transferor may use an approximation of the information, provided the approximation is clearly identified as such, is reasonable, is based on the best information available to the transferor or his or her agent, and is not used for the purpose of circumventing or evading this article.