Cal. Wat. Code § 31144.78
Upon good cause shown, an amended statement of water production may be filed or a correction of the records may be made at any time within six months of filing the water production statement. If pursuant to Section 31144.79, the owner or operator has been notified of a determination by the district that the production of water from the water-producing facility is in excess of that disclosed by the sworn statement covering the water-producing facility, and that owner or operator fails to protest the determination in the manner and in the time set forth in Section 31144.79, the owner or operator shall be precluded from later filing an amended water production statement for that period for the water-producing facility.
Ca. Water Code § 31144.78