California Code, Code of Civil Procedure - CCP § 867.5

(a) In the event that an action is brought by a public agency pursuant to this chapter, and that public agency later dismisses the action after any party has answered, then, notwithstanding Section 863, the party that answered may file an action pursuant to this chapter within 30 days after the public agency's dismissal was filed by the court.

(b) Subdivision (a) is not applicable to a case in which a public agency has by formal act rescinded the action on the matter subject to validation.