South Lahontan

100 years of California's water rights system: patterns, trends and uncertainty

Environmental Research Letters (IOP) | August 19th, 2014

For 100 years, California’s State Water Resources Control Board and its predecessors have been responsible for allocating available water supplies to beneficial uses,

For 100 years, California’s State Water Resources Control Board and its predecessors have been responsible for allocating available water supplies to beneficial uses, but inaccurate and incomplete accounting of water rights has made the state ill-equipped to satisfy growing societal demands for water supply reliability and healthy ecosystems. Here, we present the first comprehensive evaluation of appropriative water rights to identify where, and to what extent, water has been dedicated to human uses relative to natural supplies. The results show that water right allocations total 400 billion cubic meters, approximately five times the state’s mean annual runoff. In the state’s major river basins, water rights account for up to 1000% of natural surface water supplies, with the greatest degree of appropriation observed in tributaries to the Sacramento and San Joaquin Rivers and in coastal streams in southern California. Comparisons with water supplies and estimates of actual use indicate substantial uncertainty in how water rights are exercised. In arid regions such as California, over-allocation of surface water coupled with trends of decreasing supply suggest that new water demands will be met by re-allocation from existing uses. Without improvements to the water rights system, growing human and environmental demands portend an intensification of regional water scarcity and social conflict. California’s legal framework for managing its water resources is largely compatible with needed reforms, but additional public investment is required to enhance the capacity of the state’s water management institutions to effectively track and regulate water rights.

2019 Annual Compliance Report California Drinking Water Program

California State Water Resources Control Board (SWRCB) | May 1st, 2020

The State Water Resources Control Board (State Water Board) Division of Drinking Water (DDW) is the primacy agency responsible for the administration and enforc

The State Water Resources Control Board (State Water Board) Division of Drinking Water (DDW) is the primacy agency responsible for the administration and enforcement of the federal Safe Drinking Water Act (SDWA) requirements in California. The State Water Board has adopted statutes and regulations to implement the requirements of the SDWA. The State Water Boards’ regulatory responsibility over public water systems includes (1) issuance of operating permits, (2) conducting inspections and sanitary surveys, (3) monitoring for compliance with regulations, and (4) taking enforcement action to compel compliance when violations are identified. Throughout the year and as part of DDW’s regulatory oversight responsibilities, Drinking Water Program staff from DDW’s 24 District offices and 30 County health departments (delegated by the State Water Board to undertake regulatory oversight on behalf of DDW) document and record violations incurred by public water systems. Enforcement actions are issued by the Drinking Water Program to address these violations. The data is compiled and submitted to the United States Environmental Protection Agency (USEPA) on a quarterly basis. This report presents an accounting of the violations record for the calendar year 2019. USEPA requires states to issue this Annual Compliance Report by July 1st of each year and make the report available to the public.

2020 Water Resilience Portfolio (draft)

California Natural Resources Agency (CNRA) | January 2nd, 2020

2020-2022 Integrated Report For Clean Water Act Sections 303(D) And 305(B)

State of California | February 16th, 2022

2021 Drinking Water Needs Assessment

California State Water Resources Control Board (SWRCB) | April 9th, 2021

In 2016, the California State Water Resources Control Board (State Water Board) adopted a Human Right to Water Resolution making the Human Right to Water (HR2W), as defin

In 2016, the California State Water Resources Control Board (State Water Board) adopted a Human Right to Water Resolution making the Human Right to Water (HR2W), as defined in Assembly Bill 685, a primary consideration and priority across all of the state and regional boards’ programs. The HR2W recognizes that “every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking and sanitary purposes.”  In 2019, to advance the goals of the HR2W, California passed Senate Bill 200 (SB 200), which enabled the State Water Board to establish the Safe and Affordable Funding for Equity and Resilience (SAFER) Program. SB 200 established a set of tools, funding sources, and regulatory authorities that the State Water Board harnesses through the SAFER Program to help struggling water systems sustainably and affordably provide safe drinking water.  The annual Drinking Water Needs Assessment (Needs Assessment) required to be carried out by the SAFER Program provides foundational information and recommendations to guide this work. The Needs Assessment is comprised of Risk Assessment, Affordability Assessment, and Cost Assessment components. Development of the Needs Assessment consisted of stages between September 2019 and March 2021, each of which were detailed in publicly-available white papers and presented at public webinars. The public feedback was incorporated into the final methodology and results. 

2022 Annual Water Supply and Demand Assessment Summary Report

California Department of Water Resources (DWR) | November 22nd, 2022

This summary report contains projected water shortage information at the urban water supplier level as well as regional and statewide analyses of water supply conditions

This summary report contains projected water shortage information at the urban water supplier level as well as regional and statewide analyses of water supply conditions and is intended to inform the State Water Resources Control Board (State Water Board). Additionally, the report includes information on water shortage response actions taken by urban water suppliers as a result of their Annual Water Supply and Demand Assessments (Annual Assessments), and urban water suppliers’ compliance statistics with respect to their Annual Water Shortage Assessment Report (Annual Shortage Report) submittals. The purpose of this Annual Water Supply and Demand Assessment Summary Report (Summary Report) is to fulfill the California Water Code (CWC) §10644(c)(1)(B) requirements and it is due on or before September 30, 2022, and every year thereafter. The full text of the CWC section regarding the Department of Water Resources’ (DWR) Summary Report to the State Water Board is presented below for reference.

2022 Climate Action Plan Implementation Progress Report

Metropolitan Water District of Southern California (MWD) | April 30th, 2023

The CAP is a blueprint for how Metropolitan will cost-effectively reduce emissions from its operations, including those associated with water delivered through the Colora

The CAP is a blueprint for how Metropolitan will cost-effectively reduce emissions from its operations, including those associated with water delivered through the Colorado River Aqueduct (CRA).1 The CAP sets targets for reducing greenhouse gas (GHG) emissions from Metropolitan’s operations, including conveyance, storage, treatment, and delivery of water to its 26 member water agencies across its 5,200 square-mile service area, and complements Metropolitan’s existing long-range planning efforts, including the Integrated Water Resources Plan, Energy Sustainability Plan, Capital Investment Plan, and the Climate Adaptation Master Plan for Water which is currently being developed.2,3,4 The CAP also helps Metropolitan prepare for future regulations while supporting California’s GHG emission reduction goals.

2022 Drinking Water Needs Assessment

California State Water Resources Control Board (SWRCB) | April 30th, 2022

The Needs Assessment is comprised of Risk, Affordability, and Cost Assessment components. Enhancement of the 2022 Needs Assessment consisted of internal workgroup recomme

The Needs Assessment is comprised of Risk, Affordability, and Cost Assessment components. Enhancement of the 2022 Needs Assessment consisted of internal workgroup recommendations and a public workshop in February 2022, all of which were detailed in a publicly available white paper. The public feedback was incorporated into the final methodology and results. Three different water system types: public water systems, state small water systems and domestic wells, are analyzed within the 2022 Needs Assessment. Different methodologies were developed for these system types based on data availability and reliability.

2023 Annual Water Supply and Demand Assessment Summary Report

California Department of Water Resources (DWR) | September 30th, 2023

This annual report summarizes the Department of Water Resources’ (DWR’s) review of Urban Water Suppliers’ Annual Water Shortage Assessment Reports (Annual Shortage

This annual report summarizes the Department of Water Resources’ (DWR’s) review of Urban Water Suppliers’ Annual Water Shortage Assessment Reports (Annual Shortage Reports) for the State Water Resources Control Board (State Water Board). As directed by the California Water Code (CWC) §10644(c)(1)(B), this summary report includes water shortage information at the supplier level, as well as regional and statewide analyses of water supply conditions.

2023 Drinking Water Needs Assessment

California State Water Resources Control Board (SWRCB) | April 30th, 2023

The Needs Assessment is comprised of four core components: the Failing Water System List (Failing list), the Risk Assessment, the Cost Assessment, and the Affordability A

The Needs Assessment is comprised of four core components: the Failing Water System List (Failing list), the Risk Assessment, the Cost Assessment, and the Affordability Assessment. Public input that the State Water Board received via workshops held in 2022 and February 2023 helped improve the 2023 Needs Assessment.