Urban Water Management Planning Guidebook for Urban Water Suppliers (2015)

California Department of Water Resources (DWR) | March 3rd, 2016

The Guidebook for Urban Water Suppliers (Guidebook) has been developed by Department of Water Resources to assist urban water suppliers in preparing 2015 Urban Water Mana

The Guidebook for Urban Water Suppliers (Guidebook) has been developed by Department of Water Resources to assist urban water suppliers in preparing 2015 Urban Water Management Plans (UWMPs or Plans). This guidance is intended to ensure the Plans will address the requirements of the California Water Code (CWC), provide useful information to the public about water suppliers and their water management programs, and provide a framework for water planning to minimize the negative effects of potential water shortages. Water suppliers need not limit themselves to the requirements and recommendations found in the Guidebook. Suppliers may include any additional information that will assist in providing a full description of their water resources and water management.

Urban Water Revolution: Sustainable Water Futures for California Cities

American Society of Civil Engineers (ASCE) | July 15th, 2020

California has consistently altered natural water resources to provide water for its growing population and to support the fifth largest economy in the world. However, th

California has consistently altered natural water resources to provide water for its growing population and to support the fifth largest economy in the world. However, the old ways of coping with the California’s urban water needs—overdraft of groundwater, stream depletion, and greater imports—will no longer meet the demands of the 21st century. We examine California’s water history and present several promising solutions to the challenge of urban water security: a combination of conservation and efficiency, desalination, stormwater capture, water re-use, and water banking. These options for urban water, including direct potable reuse, will help dry cities in California and elsewhere achieve more sustainable and diversified water supply portfolios. Pilot and demonstration-scale projects, along with innovations in systems management and new regulations, point the way toward more resilient water supplies for dry cities. Movement toward regional collaboration, implementation of new technologies, and new regulatory regimes are helping to realize a one-water vision. Different cities will develop their own water supply portfolio options appropriate for their geography, values, and urban form on a path toward meeting the urban water challenges of this century.

Using Watershed Science to Build Consensus and Maximize Benefits of L.A. County’s Safe Clean Water Program

Accelerate Resilience LA (ARLA) | January 31st, 2022

To meet its diverse goals, SCWP scoring criteria, processes, and guidelines were initially developed to incentivize projects that simultaneously address water, environmen

To meet its diverse goals, SCWP scoring criteria, processes, and guidelines were initially developed to incentivize projects that simultaneously address water, environmental, MS4 compliance, and social issues. However, the first two SCWP funding cycles of Stormwater Investment Plans (SIP) featured extensive committee debate and public comments concerning the balance of these goals. This public debate illuminated the need for an assessment of the extent to which SCWP guidance, criteria, structure, and processes are successfully driving meaningful progress toward the fourteen SCWP Goals.

Utah's Land, Water and Air 2022 Report to the Governor

Utah State University | November 30th, 2022

Waste Not, Want Not: The Potential for Urban Water Conservation in California

Pacific Institute | November 1st, 2003

The largest, least expensive, and most environmentally sound source of water to meet California’s future needs is the water currently being wasted in every sector of

The largest, least expensive, and most environmentally sound source of water to meet California’s future needs is the water currently being wasted in every sector of our economy. That’s the core message of a major new report on urban water use in California released by the Pacific Institute of Oakland, California. “Waste Not, Want Not: The Potential for Urban Water Conservation in California,”in preparation for three years, is the first report to look comprehensively at residential, commercial, institutional, and industrial water use in the state — and then evaluate the potential for reducing this use through conservation and efficiency. Despite the progress California has already made in improving water efficiency, “Waste Not, Want Not” estimates that up to one-third of California’s current urban water use — more than 2.3 million acre-feet — can be saved using existing technology. And at least 85% of this savings (over 2 million acre-feet) can be saved at costs below what it will cost to tap into new sources of supply and without the social, environmental, and economic impacts that any major water project will bring.

Wastewater Reuse for Agriculture: Development of a Regional Water Reuse Decision-Support Model (RWRM) for Cost-Effective Irrigation Sources

American Chemical Society (ACS) | August 8th, 2016

Water scarcity has become a critical problem in many semiarid and arid regions. The single largest water use in such regions is for crop irrigation, which typically relie

Water scarcity has become a critical problem in many semiarid and arid regions. The single largest water use in such regions is for crop irrigation, which typically relies on groundwater and surface water sources. With increasing stress on these traditional water sources, it is important to consider alternative irrigation sources for areas with limited freshwater resources. One potential irrigation water resource is treated wastewater for agricultural fields located near urban centers. In addition, treated wastewater can contribute an appreciable amount of necessary nutrients for plants. The suitability of reclaimed water for specific applications depends on water quality and usage requirements. The main factors that determine the suitability of recycled water for agricultural irrigation are salinity, heavy metals, and pathogens, which cause adverse effects on human, plants, and soils. In this paper, we develop a regional water reuse decision-support model (RWRM) using the general algebraic modeling system to analyze the cost-effectiveness of alternative treatment trains to generate irrigation water from reclaimed wastewater, with the irrigation water designed to meet crop requirements as well as California’s wastewater reuse regulations (Title 22). Using a cost-minimization framework, least-cost solutions consisting of treatment processes and their intensities (blending ratios) are identified to produce alternative irrigation sources for citrus and turfgrass. Our analysis illustrates the benefits of employing an optimization framework and flexible treatment design to identify cost-effective blending opportunities that may produce high-quality irrigation water for a wide range of end uses.

Water and Wastes: A Retrospective Assessment of Wastewater Technology in the United States, 1800-1932

Johns Hopkins University Press (Hopkins Press) | April 2nd, 1984

This article derives largely from our NSF report on wastewater technology. The specific objects of the research were to identify the processes and key decision points i

This article derives largely from our NSF report on wastewater technology. The specific objects of the research were to identify the processes and key decision points involved in the evolution of wastewater technology of human waste disposal, to explore both its primary and secondary social and institutional effects, and to examine the development of public policy toward water pollution problems. In addition, the report dealt with the role played by values in the implementation of technology, as well as the effect of the technology on values. The essential aims of the project were to increase our understanding of water-related environmental problems and to inform policymakers about the larger context of contemporary wastewater questions.

Water conservation benefits of urban heat mitigation

Nature Portfolio (Springer Nature) | October 20th, 2017

Many cities globally are seeking strategies to counter the consequences of both a hotter and drier climate. While urban heat mitigation strategies have been sho

Many cities globally are seeking strategies to counter the consequences of both a hotter and drier climate. While urban heat mitigation strategies have been shown to have beneficial effects on health, energy consumption, and greenhouse gas emissions, their implications for water conservation have not been widely examined. Here we use a suite of satellite- supported regional climate simulations in California to show that broad implementation of cool roofs, a heat mitigation strategy, not only results in significant cooling, but can also meaningfully decrease outdoor water consumption by reducing evaporative and irrigation water demands. Irrigation water consumption across the major metropolitan areas is reduced by up to 9% and irrigation water savings per capita range from 1.8 to 15.4 gallons per day across 18 counties examined. Total water savings are found to be the highest in Los Angeles county, reaching about 83 million gallons per day. Cool roofs are a valuable solution for addressing the adaptation and mitigation challenges faced by multiple sectors in California.

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 Footprint Outcomes and Policy Relevance Change with Scale Considered: Evidence from California

Pacific Institute | September 1st, 2014

A new article by Julian Fulton, Heather Cooley, and Peter Gleick evaluates California’s water footprint, finding that California’s water footprint demonstrate a set o

A new article by Julian Fulton, Heather Cooley, and Peter Gleick evaluates California’s water footprint, finding that California’s water footprint demonstrate a set of vulnerabilities and policy options that do not emerge in national-level assessments. The article, published in Water Resources Management, demonstrates that water footprint assessments may find greater policy relevance when scaled to analytical units where water-related decision making occurs. Abstract: Methods and datasets necessary for evaluating water footprints have advanced in recent years, yet integration of water footprint information into policy has lagged. One reason for this, we propose, is that most studies have focused on national units of analysis, overlooking scales that may be more relevant to existing water management institutions. The authors of Water Footprint Outcomes and Policy Relevance Change with Scale Considered: Evidence from California illustrate this by building on a recent water footprint assessment of California, the third largest and most populous state in the United States. While California contains diverse hydrologic regions, it also has an overarching set of water institutions that address statewide water management, including ensuring sustainable supply and demand for the state’s population and economy. The water footprint sheds new light on sustainable use and, in California, is being considered with a suite of sustainability indicators for long-term state water planning. Key to this integration has been grounding the method in local data and highlighting the unique characteristics of California’s water footprint, presented here. Compared to the U.S., California’s water footprint was found to be roughly equivalent in per-capita volume (6 m3d-1) and constituent products, however two  policy-relevant differences stand out: (1) California’s water footprint is far more externalized than the U.S.’s, and (2) California depends more on “blue water” (surface and groundwater) than on “green water” (rainwater and soil moisture). These aspects of California’s water footprint suggest a set of vulnerabilities and policy options that do not emerge in national-level assessments. Such findings demonstrate that water footprint assessments may find more policy relevance when scaled to analytical units where water-related decision making occurs.