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.

Water Forward 2024 Plan Report - Austin's 100 Year Plan

City of Austin | December 6th, 2024

Water Forward 2024 is Austin’s 100-year integrated water resource plan. The purpose of Water Forward is to develop and implement diverse and environmentally conscious w

Water Forward 2024 is Austin’s 100-year integrated water resource plan. The purpose of Water Forward is to develop and implement diverse and environmentally conscious water management strategies to adapt to growth, drought, and climate change and ensure a sustainable, resilient, equitable, and affordable water future for our community for the next 100 years. Austin Water has developed this plan to address near- and long-term water needs through a collaborative process in alignment with guiding principles crafted to reflect the Austin community’s values. 

Water Loss Audit Manual

California Department of Water Resources (DWR) | February 11th, 2016

This document is intended to provide guidance on preparing a distribution system water loss audit in accordance with the American Water Works Association (AWWA) Manual 36

This document is intended to provide guidance on preparing a distribution system water loss audit in accordance with the American Water Works Association (AWWA) Manual 36. The guidance was prepared specifically as a reference for California water suppliers. To improve water loss reporting in California, SB 1420 (2014) was passed requiring water suppliers to submit water loss audits as part of urban water management plans prepared once every five years. SB 555 (2015) builds on SB 1420 and requires, beginning in 2017, the submittal of annual water loss reports to the California Department of Water Resources (DWR) that have been validated for data accuracy. This guide should be helpful, but is not intended to be a substitute for the AWWAs Manual 36. Water loss audits are a valuable tool in identifying and prioritizing distribution system leaks that when addressed can improve the efficiency of water production and delivery for all water suppliers by reducing losses.

Water Partnerships between Cities and Farms in Southern California and the San Joaquin Valley

Public Policy Institute of California (PPIC) | October 29th, 2020

The San Joaquin Valley and urban Southern California are worlds apart in many ways. Yet each face growing water challenges and a shared interest in ensuring reliable, aff

The San Joaquin Valley and urban Southern California are worlds apart in many ways. Yet each face growing water challenges and a shared interest in ensuring reliable, affordable water supplies to safeguard their people and economies. Both regions’ water futures could be more secure if they take advantage of shared water infrastructure to jointly develop and manage some water supplies.  Increasing climate volatility is heightening concerns about droughts of the future. And two major shifts in California’s water landscape have generated new opportunities for collaboration between urban and agricultural interests. For urban areas, significant declines in water demand have reduced pressure on supplies during normal and wet years for many agencies, making reliability for future droughts the primary concern. For the overdrafted San Joaquin Valley, the requirement to manage groundwater sustainably has heightened interest in expanding water supplies and underground storage.  Partnerships between Southern California cities and San Joaquin Valley farms could help alleviate groundwater overdraft in the valley while building drought resilience in Southern California. More flexible supplies can help agencies adapt to changing conditions. By coordinating the location of infrastructure investments, agencies can use partnerships to bring the water where and when it is most needed, at least cost.  This report explores a variety of solutions that could benefit both regions. For the San Joaquin Valley, we look for ways to augment water supplies to ease the transition to groundwater sustainability, while for Southern California we explore options that would increase cities’ ability to deal effectively with extended droughts. By diversifying water supplies, building connections to share water more flexibly, and preparing for the extreme events to come, such partnerships would support Governor Newsom’s Water Resilience Portfolio, and pave the way for a shared effort to make the state’s water system more resilient to a changing climate.