Guide for Developing Onsite Water Systems to Support Regional Water Resilience

Pacific Institute | January 26th, 2023

Across the United States, urban communities face growing water challenges, from water scarcity to flooding, pollution, aging water infrastructure, and more. These challen

Across the United States, urban communities face growing water challenges, from water scarcity to flooding, pollution, aging water infrastructure, and more. These challenges present risks, but also an opportunity to rethink how we manage water, including adopting circular approaches in new buildings that reduce their water footprint and improve urban water resilience. Onsite water systems, for example, collect, treat, and reuse water from onsite sources, including wastewater, rainwater, and stormwater, for non-potable water uses like toilet flushing, outdoor irrigation, and cooling. Onsite water systems have the potential to provide multiple benefits for a site, water and wastewater systems, ecosystems, and communities. They can, for example, help companies mitigate water- related risks, like water shortages that threaten to disrupt business operations, and support corporate water stewardship goals. For communities, onsite water systems can enhance water supply reliability, improve water quality, reduce localized flooding, and increase urban green space. The realization and magnitude of benefits will vary with the type of system, scale of adoption, and other context-specific factors. This guide helps site developers consider how onsite water systems can be planned, designed, and operated to provide multiple benefits, and contribute to planning and designing onsite water systems that advance water resilience, support equity, support the environment, and protect public health at the site, water system, and community scales. For each of these outcomes, the guide provides sample questions to consider, stakeholders to engage, resources to examine, and analyses to perform.

Guidebook to Assist Urban Water Suppliers to Prepare a 2010 Urban Water Management Plan

California Department of Water Resources (DWR) | March 17th, 2011

Guidebook to Assist Urban Water Suppliers to Prepare a 2010 Urban Water Management Plan (Guidebook) has been developed by the California Department of Water Resources (

Guidebook to Assist Urban Water Suppliers to Prepare a 2010 Urban Water Management Plan (Guidebook) has been developed by the California Department of Water Resources (DWR) to assist urban water suppliers in complying with requirements of the Urban Water Management Planning Act (the UWMP Act) and the Water Conservation Bill of 2009. It is meant to help suppliers better understand UWMP Act requirements, but water suppliers are solely responsible for ensuring they’ve complied with the requirements of the UWMP Act or applicable laws. For the purposes of this Guidebook and the UWMP Act, urban water suppliers with 3,000 or more service connections or supplying 3,000 or more acre-feet of water per year are to prepare a UWMP every five years.

Hazy Futures: Projecting the local impacts of global warming is a stubborn challenge. But cities need answers fast

American Association for the Advancement of Science (AAAS) | June 5th, 2025

A wastewater treatment plant isn’t top on everyone’s sightseeing itinerary. But on a cloudless, breezy day in April, Agmed Weber, operations manager for the Walnut Cr

A wastewater treatment plant isn’t top on everyone’s sightseeing itinerary. But on a cloudless, breezy day in April, Agmed Weber, operations manager for the Walnut Creek plant—which handles more than half of the sewage here in Texas’s booming capital city—is an enthusiastic tour guide. He marvels at the foresight of those who built the jumbo plant a half-century ago, when Austin was a third of its current size. “They were really thinking about the future,” he says. Weber feels a similar pressure—to prepare for not only continued population growth, but also a hotter future. Austin is “in a tight space where we need to think ahead,” he says.

Hidden Oasis: Water Conservation and Efficiency in Las Vegas

Pacific Institute | November 20th, 2007

Two of the West’s preeminent water organizations report Las Vegas Valley is sitting on an oasis of water and money savings. In their new report, the Pacific Institute a

Two of the West’s preeminent water organizations report Las Vegas Valley is sitting on an oasis of water and money savings. In their new report, the Pacific Institute and Western Resource Advocates find up to 40% of water could be saved in some sectors through improvements to indoor and outdoor water efficiency. They also found that through improving indoor water efficiency in particular, Las Vegas residents and businesses can cut water-related energy use and greenhouse gases. These findings are contained in Hidden Oasis: Water Conservation and Efficiency in Las Vegas available for download below. “Ninety percent of Las Vegas’ water efficiency money is spent on one program—turf removal. This program is important, but participation has waned and it is far from the only tool at their disposal,” said Heather Cooley, report co-author and Pacific Institute Senior Associate. “Las Vegas should capitalize on strategies that other Western cities have proven to be effective.” Hidden Oasis reveals that the Southern Nevada Water Authority, which provides water to Las Vegas and surrounding communities, can tap a number of tested, cost-effective efficiency measures to cut current water waste by up to 86,000 acre-feet. Single-family homes in Las Vegas use 100 gallons of water outside, per person, per day—almost entirely for landscaping. This use is substantially higher than in Los Angeles, Tucson, or Albuquerque. Reducing Las Vegas’ outdoor water use to more reasonable levels could cut Nevada’s total Colorado River withdrawals by 10 percent. Researchers found that by improving and expanding existing programs, and adding programs proven elsewhere in the West, the SNWA can cut Las Vegas homeowners’ indoor water waste by 40% and hotel and casino water waste by 30%. These indoor efficiency gains come from upgrading fixtures and appliances, not changing behavior. Improving total water efficiency not only saves significant water and energy expenses, it also better insulates the region from drought. “Improving indoor and outdoor water efficiency makes Las Vegas less vulnerable to current and future droughts,” said Taryn Hutchins-Cabibi, report coauthor and Water Policy Analyst at WRA. “Given the scarcity of fresh water, rising energy prices, and the looming threat of climate change, Las Vegas’ water customers need the SNWA’s help to curb unnecessary water waste and save money.”

How much potable water is saved by wastewater recycling? Quasi-experimental evidence from California

Resources, Conservation & Recycling (Elsevier) | October 6th, 2021

Recently, California has made large investments in wastewater recycling to replace applications that use potable water. It may be expected that the use of recycled water

Recently, California has made large investments in wastewater recycling to replace applications that use potable water. It may be expected that the use of recycled water reduces potable water use, but such an equivalency is not assured. The addition of recycled water infrastructure in a large Californian water district creates a natural experiment where this work tests how recycled water usage affects primary potable water. This is done using econometric methods for causal inference in an observational setting that mirror a randomized control trial (RCT). From 2001 to 2014, a number of public parks were given recycled water infrastructure, while others in those regions remained exclusively on potable supply. A two-way fixed effects regression is used to produce a difference-in-differences estimate of the average treatment effect of recycled water on total and potable water usage. The results indicate that potable water usage is reduced significantly when a park is connected to the recycled water supply. The estimated rate of displacement in the study period is 81.7%, meaning each unit of recycled water use avoided 0.817 units of potable water usage, which implies the connection of parks to recycled water supply increases total water use. The analysis provides, to the best of our knowledge, the first empirical estimate of the water savings claimed by urban water recycling programs, and the first empirical estimate of displacement using quasi-experimental methods. The methodology can be utilized to evaluate the effectiveness of recycling programs around the world.

Identifying American climate change free riders and motivating sustainable behavior

Nature Portfolio (Springer Nature) | March 19th, 2024

Identifying the Amount of Wastewater that is Available and Feasible to Recycle in California

Water Research Foundation (WRF) | July 24th, 2023

Integrated irrigation and nitrogen optimization is a resource-efficient adaptation strategy for US maize and soybean production

Nature Portfolio (Springer Nature) | January 8th, 2025

Climate change poses substantial challenges to agriculture and crop production, but the combined role of nitrogen and water inputs in adaptation has been largely overlook

Climate change poses substantial challenges to agriculture and crop production, but the combined role of nitrogen and water inputs in adaptation has been largely overlooked. Here, by developing regression models using US county-level data (2008–2020), we demonstrate that integrated optimization of irrigation and nitrogen inputs represents the most resource-efficient strategy to offset the climate-related yield losses. Under the 1.5 °C (3 °C) warming scenario, this approach involves increasing irrigation water withdrawals for maize by 62% (67%) and reducing it for soybean by 65% (58%), while increasing nitrogen inputs for maize by 4% (13%) and for soybean by 10% (130%) annually. This strategy reduces unsustainable irrigation water withdrawals by 73% (56%) for maize and 26% (28%) for soybean, enhancing water sustainability. Cost–benefit analysis indicates this optimization is cost-effective for over 80% of US maize and soybean productions, underscoring its critical role for climate change adaptation.

Irrigated Agriculture Technologies, Practices, and Implications for Water Scarcity

U.S. Government Accountability Office (GAO) | November 12th, 2019

Demand for freshwater surpasses the amount naturally available in some areas of the United States. The agriculture sector competes for this limited resource, and withdraw

Demand for freshwater surpasses the amount naturally available in some areas of the United States. The agriculture sector competes for this limited resource, and withdraws and consumes the most freshwater of any user in the nation. GAO was asked to conduct a technology assessment around agricultural water use. This report provides an overview of irrigation technologies and on-farm water conservation practices, factors influencing the adoption of these technologies, and implications of their use for water scarcity. In conducting this assessment, GAO reviewed scientific literature; convened an expert meeting with the assistance of the National Academies; visited farmers, academics, and industry representatives; interviewed officials from federal agencies; modeled water use in an illustrative watershed; and performed a regression analysis on U.S. Department of Agriculture irrigation, crop, and technology data. GAO describes two policy options that federal policymakers could consider relating to irrigation technology and discusses their benefits and challenges.

Irrigation in the Earth system

Nature Portfolio (Springer Nature) | June 20th, 2023