Public Utilities Code § 14402

A district or any interested person may bring an action pursuant to Chapter 9 (commencing with Section 860) of Title 10 of Part 2 of the Code of Civil Procedure to determine the validity of district rates or charges.

Notwithstanding any other provision of law, any judicial action or proceeding to attack, review, set aside, void, or annul an ordinance, resolution, or motion fixing or changing rates or charges for the commodities or service furnished by a district shall be commenced within 120 days of the effective date of the ordinance, resolution, or motion.