Water Measurement and Reporting Regulation Revisions

The State Water Resources Control Board of California is implementing revisions to water measurement and reporting regulations through Resolution No. 2025-0021 to modernize the data submission process and improve the quality of water diversion data. These changes align reporting requirements with the CalWATRS online platform, which is expected to launch in late 2025. The revisions standardize data formats to be machine-readable, update reporting periods to follow the water year from October 1 to September 30, and expand alternative compliance options under Water Code section 1840(b)(1). Additionally, measurement requirements are being eliminated for small diverters, including those used for domestic purposes, livestock, and cannabis irrigation. The regulatory action is effective October 1, 2025, with full integration into CalWATRS and the first reporting cycle expected by January 2026. The primary objective is to enhance data usability and submission rates while balancing costs for water diverters. This action is categorized as a forecast and is governed by the California Code of Regulations, Title 23, and various sections of the Water Code. The process has been determined to be CEQA-exempt due to minimal environmental impact. Contact for this initiative is Samantha Olson, Attorney IV for the State Water Resources Control Board.