California Code, Civil Code - CIV § 1798.199.75

(a) In addition to any other available remedies, the agency may bring a civil action and obtain a judgment in superior court for the purpose of collecting any unpaid administrative fines imposed pursuant to this title after exhaustion of judicial review of the agency's action. The action may be filed as a small claims, limited civil, or unlimited civil case depending on the jurisdictional amount. The venue for this action shall be in the county where the administrative fines were imposed by the agency. In order to obtain a judgment in a proceeding under this section, the agency shall show, following the procedures and rules of evidence as applied in ordinary civil actions, all of the following:

(b) A civil action brought pursuant to subdivision (a) shall be commenced within four years after the date on which the administrative fines were imposed.