South Lahontan

Water Allocation in California - Legal Rights and Reform Needs

Golden Gate University (GSU) | March 31st, 1982

FOREWARD: Water supply, allocation, use and conservation are constantly debated in California, often appearing as highly charged political issues in candidates' races and

FOREWARD: Water supply, allocation, use and conservation are constantly debated in California, often appearing as highly charged political issues in candidates' races and on election ballots. This year is no exception, with major ballot propositions already scheduled for the June primary election and being circulated to qualify for the November general election. Accordingly this Research Paper on legal aspects of water allocation is being published for the valuable background it affords readers wishing to learn more about the subject. The author draws on his legal expertise, as well as his experience as Staff Director of the Governor's Commission to Review California Water Rights Law. The paper emphasizes the crucial role of water rights in California water management, and it points to the need for and present lack of a political consensus on water law reform. The author concludes by suggesting forces that could bring about interest-group realignments and other developments favorable to achieving the needed consensus on water law and management reform that so far has eluded Californians. Stanley Scott Assistant Director Institute of Governmental Studies March 1982

Water and Energy in California

Public Policy Institute of California (PPIC) | December 6th, 2022

Water Available for Replenishment 2018

California Department of Water Resources (DWR) | April 12th, 2018

Water Demand Projection Accuracy and Demand Management Trends in California Cities

American Geophysical Union (AGU) | November 21st, 2025

This study investigates the accuracy of long-term water demand projections and tracks the evolution of water demand management incentives across 61 California water suppl

This study investigates the accuracy of long-term water demand projections and tracks the evolution of water demand management incentives across 61 California water suppliers from 2000 to 2020. Through a systematic analysis of Urban Water Management Plans, we find that water suppliers consistently overestimated future demand by an average of 25% for 5-year projections and 74% for 20-year projections. This overestimation stems primarily from assumptions about per capita water demand rather than population growth estimates. While suppliers generally projected stable or increasing per capita demand, actual water demand per capita declined by 1.9% annually between 2000 and 2020, leading to a decoupling of water demand from population growth. Concurrently, we document a substantial increase in water demand management incentives, with non-voluntary regulations emerging as the dominant demand management approach by 2020, largely driven by state policies like the Model Water Efficient Landscape Ordinance and California Green Building Standards. Demand management efforts have evolved from primarily indoor and educational initiatives toward outdoor-focused non-voluntary regulations and rebates. This shift appears closely linked to the reduction in per capita demand that suppliers failed to fully capture in their water demand projections. Our findings underscore the importance of incorporating dynamic conservation trends into demand projections and suggest that suppliers should develop more sophisticated forecasting methods that account for the continuing evolution of water efficiency incentives. This research provides valuable insights for water resource planners seeking to improve the accuracy of water demand projections in an era of increasing conservation and climate uncertainty.

Water Quality Control Plan for the Lahontan region

Lahontan Regional Water Quality Control Board (LRWQCB) | December 15th, 2015

Water quality standards and control measures for surface and ground waters of the Lahontan Region are contained in the Water Quality Control Plan for the Lahontan Region

Water quality standards and control measures for surface and ground waters of the Lahontan Region are contained in the Water Quality Control Plan for the Lahontan Region (Basin Plan). The plan designates beneficial uses for water bodies and establishes water quality objectives, waste discharge prohibitions, and other implementation measures to protect those beneficial uses. State water quality standards also include a Nondegradation Policy. Water quality control measures include Total Maximum Daily Loads (TMDLs), which are often, but not always, adopted as Basin Plan amendments. See the Lahontan Water Board’s TMDL Program web page for further information. The Lahontan Basin plan took effect in 1995, replacing three earlier plans. The current edition of the plan includes fully approved sets of amendments adopted since 1995. Chapters and sections of the plan are available in separate files to facilitate downloading. In addition to the state standards in the Basin Plan, federal water quality standards for certain toxic pollutants apply to surface waters within California, including the Lahontan Region. These standards are contained in the National Toxics Rule (40 CFR 131.36) and the California Toxics Rule (40 CFR 131.37). The California State Water Resources Control Board (SWRCB) has adopted a statewide implementation policy for the federal toxics standards, including summary tables listing the standards themselves. The federal standards have not yet been physically incorporated into the Basin Plan. The National Toxics Rule and California Toxics Rule standards differ from federal water quality criteria in that they are enforceable. Federal criteria are non-enforceable, science-based thresholds that can be used in development of enforceable state water quality standards. For the latest information on this water quality control plan, including any amendments, click here.

Water quality for agriculture

Food and Agriculture Organization of the United Nations (FAO) | July 15th, 1985

Water Quality in Basin-Fill Aquifers of the Southwestern United States: Arizona, California, Colorado, Nevada, New Mexico, and Utah, 1993–2009

U.S. Geological Survey (USGS) | July 15th, 2014

Water Quality in California

Public Policy Institute of California (PPIC) | February 23rd, 2026

Water Quality of Groundwater Used for Public Supply in Principal Aquifers of the Western United States

U.S. Geological Survey (USGS) | September 8th, 2020

Water Right Exactions

Social Science Research Network (SSRN) | May 15th, 2023