Groundwater adjudication.

Assembly Member Hart's groundwater adjudication reform measure modifies California's procedures for determining water rights in comprehensive basin adjudications, introducing new mechanisms to process claims from minor extractors and integrate technical data from sustainability agencies.

Courts may now either exempt parties extracting less than five acre-feet annually or process their claims separately to reduce participation burdens while maintaining their rights. For extractors claiming under 100 acre-feet per year or amounts deemed reasonable by the court, the accuracy of initial disclosure statements is presumed, placing the burden of proof on challenging parties to demonstrate inaccuracies.

In basins with approved sustainability plans, courts must request technical reports from groundwater sustainability agencies to quantify and describe water use by non-appearing parties. These reports serve as prima facie evidence of physical facts, though parties retain the right to present rebuttal evidence. The legislation establishes a cost recovery framework requiring courts to equitably apportion expenses among parties while prohibiting agencies from charging fees for report preparation.

The amendments preserve existing provisions for special master appointments, surface water considerations, and sustainability planning requirements while adding tools to streamline adjudications through standardized forms, electronic filing, and verification procedures. These changes aim to expedite groundwater rights determinations while maintaining comprehensive basin management approaches.