Recommendations to the State Water Resources Control Board Pursuant to California Water Code Section 10609

California Department of Water Resources (DWR) | September 29th, 2022

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and Assembly Bill 1668 [Friedman]) enacted in support of “Making Water Conservation a California Way of Life.” The Legislation included provisions for advancing urban water use efficiency through developing and implementing various water use efficiency standards, variances for unique uses of water, and commercial, industrial, and institutional (CII) performance measures, among other requirements. Full reports detailing our methods, technical analyses, studies, public input, and recommendations will follow. These recommendations for long-term urban water use efficiency reflect technical considerations, public input, and the imperative to continue California’s progress in urban efficient use of water for future generations. If adopted DWR's recommendations on outdoor residential and CII water use on landscapes with dedicated irrigation meters, combined with the indoor residential water use standard recommendations submitted to the Legislature jointly by DWR and State Water Resources Control Board (State Water Board), pursuant to Water Code 10609.4 (b)(1), would result in expected long-term water savings of approximately 450,000 acre-feet per year starting in 2030 – considering 2019 population and 2017-2019 water use data, the water savings are enough to supply about 1.6 million homes or 4.7 million residents for both indoor and outdoor annual water needs.

Reimagining Water Infrastructure in a Changing California

American Water Resources Association (AWRA) | April 15th, 2023

For much of the 20th century, California’s water supply strategy has relied on building large reservoirs and conveyance systems to store and divert surface water and dr

For much of the 20th century, California’s water supply strategy has relied on building large reservoirs and conveyance systems to store and divert surface water and drilling ever deeper wells to tap declining aquifers. This approach has brought many benefits but has also come at great social, economic, and environmental costs. Moreover, these traditional water supplies are tapped out. Even in wet years, the state’s major rivers are overallocated and major aquifers severely overdrafted. Dry years intensify these issues. Persistent water challenges, the severe drought, and the intensifying effects of climate change highlight the vulnerability of California’s water systems and the need for new approaches.

Residential End Uses of Water, Version 2: Executive Report

Water Research Foundation (WRF) | April 14th, 2016

It is essential for water providers and the urban water supply industry to have a detailed understanding of how water is usedin residential settings. While water

It is essential for water providers and the urban water supply industry to have a detailed understanding of how water is usedin residential settings. While water use in homes was studied as early as the 1940s, interest intensified after the Energy Policy Act of 1992, which sought to improve energy and water efficiency. This Act established maximum flow rates for new residential toilets, showerheads, and faucets. Later federal regulations included clothes washers. Water efficiency in homes has also been encouraged by programs like EPA’s WaterSense. Until now, the most significant residential end use study conducted in North America was the Water Research Foundation’s 1999 report, Residential End Uses of Water (REU1999) (Mayer et al. 1999). WRF’s newreport, Residential End Uses of Water, Version 2 (REU2016) (DeOreo et al. 2016), provides an updated and expanded assessment of water use. It includes more varied study site locations, hot water usage data, more detailed landscape analysis, and additional water rate analysis. The new study identifies variations in water use by each fixture or appliance, providing detailed information and data on changes since the REU1999 study. Looking to the future, the study’s research evaluates conservation potential, and includes predictive models to forecast residential demand. The decline in water use across the residential sector, even as populations increase, poses new challenges for water utilities. Information on single family home water consumption is significant for utility rate and revenue projections, capital planning (water supply and infrastructure needs), daily operations to provide water, water efficiency programs, and more.

Residential Water Conservation and the Rebound Effect: A Temporal Decomposition and Investigation

American Geophysical Union (AGU) | April 25th, 2023

Resilient Los Angeles

City of Los Angeles | March 1st, 2018

Los Angeles has always been a global destination for dreamers, doers, thinkers, and creators. We have blue skies and pristine beaches and a rich culture of diversity, c

Los Angeles has always been a global destination for dreamers, doers, thinkers, and creators. We have blue skies and pristine beaches and a rich culture of diversity, creativity, and entrepreneurism. The opportunities of tomorrow are limitless, as we work to build Los Angeles into a vibrant, thriving model city of the 21st century. Yet this dream comes with the growing pressures of our susceptibility to the impacts of climate change and aging infrastructure. We are all deeply aware that it is a question of when, not if Los Angeles will face the next Big One—whether it’s an earthquake, flood, heatwave, fire, or other disaster with long-term impacts. While we have made great strides over the past 25 years, it’s time to do more—to strengthen and create new partnerships, to change the way our government collaborates and to empower and secure our communities—so that we can work together to make L.A. a global model of resilience. Building a more resilient Los Angeles starts with addressing the needs of our most vulnerable populations and neighborhoods. Too often, those who are least equipped to handle the effects of catastrophic events end up suffering the most. And empowering our most vulnerable—children, immigrants, and lower-income residents, among others—is not just about emergency preparedness. It is about directly addressing those underlying daily stresses—such as poverty, financial security, and affordable housing—and ensuring that all Angelenos feel safe and secure in their daily lives. It also means bringing neighbors together to strengthen our collective resources and social bonds and innovating creative solutions along the way.

Santa Clara Valley Water District 2015 Urban Water Management Plan

Santa Clara Valley Water District | May 1st, 2016

The Urban Water Management Planning Act (UWMP Act) (Division 6 Part 2.6 of California Water Code §10610 - 10656) requires the preparation of an Urban Water Management P

The Urban Water Management Planning Act (UWMP Act) (Division 6 Part 2.6 of California Water Code §10610 - 10656) requires the preparation of an Urban Water Management Plan (UWMP) every five years by water suppliers that provide over 3,000 acre-feet of water annually or serve water for municipal purposes either directly or indirectly to 3,000 or more customers. The Santa Clara Valley Water District (District) meets the definition of an urban water supplier and has prepared UWMPs since 1985. This 2015 UWMP documents important information on water supply, water usage, recycled water, water conservation programs, water shortage contingency planning, and water supply reliability in Santa Clara County. It also serves as a valuable resource for water supply planners and policy makers, and addresses the water supply future of Santa Clara County over the next 25 years. The 2015 UWMP updates and supersedes all previous UWMPs.... The District is an independent special district that provides wholesale water supply, groundwater management, flood protection and stream stewardship. Its service area includes all of Santa Clara County, which is located at the southern end of San Francisco Bay (Figure 3-1). The county encompasses approximately 1,300 square miles and has a population of about 1.9 million. Most water use occurs on the valley floor between the Santa Cruz Mountains to the west and the Diablo Range to the east. Northern Santa Clara County is home to Silicon Valley and the valley floor is highly urbanized. Southern Santa Clara County has some urban development, but much of the land use is still rural and agricultural. Click here for appendices

Saving Water and Money through Toilet Leak Detection

Pacific Institute | April 1st, 2024

This report discusses a cross-sector pilot project that deployed toilet leak detection technology in eight affordable multifamily properties in Los Angeles, California in

This report discusses a cross-sector pilot project that deployed toilet leak detection technology in eight affordable multifamily properties in Los Angeles, California in 2023. Periodic droughts, and prolonged drying trends driven by climate change, are reducing the reliability of Los Angeles’ water supplies. Water efficiency and conservation are key strategies to ensure water resilience in the face of these changes.

Securing Color River Supplies - An Urban-Agriculture Partnership in the Palo Verde Valley

Metropolitan Water District of Southern California (MWD) | March 16th, 2022

Senate Bill No. 1157

State of California | September 28th, 2022

Shifting landscapes: decoupled urban irrigation and greenness patterns during severe drought

Environmental Research Letters (IOP) | June 7th, 2019

Urban outdoor water conservation and efficiency offer high potential for demand-side management, but irrigation, greenness, and climate interlinks must be better underst

Urban outdoor water conservation and efficiency offer high potential for demand-side management, but irrigation, greenness, and climate interlinks must be better understood to design optimal policies. To identify paired transitions during drought, we matched parcel-level water use data from smart, dedicated irrigation meters with high-spatial resolution, multispectral aerial imagery. We examined changes across 72 non-residential parcels using potable or recycled water for large landscape irrigation over four biennial summers (2010, 2012, 2014, and 2016) that encompassed a historic drought in California. We found that despite little change in irrigation levels during the first few years of the drought, parcel greenness deteriorated. Between summers 2010 and 2014, average parcel greenness decreased−61% for potable water irrigators and−56% for recycled water irrigators, providing evidence that vegetation could not reach its vigor from wetter, cooler years as the drought intensified with abnormally high temperatures. Between summers 2014–2016 as drought severity lessened, irrigation rates decreased significantly in line with high drought saliency, but greenness rebounded ubiquitously, on average+110% for potable water irrigators and+62% for recycled water irrigators, demonstrating climate-driven vegetation recovery as evaporation and plant evapotranspiration rates decreased. Transitions were similar for customers with both potable and recycled water; vegetation changes were dominated by the overarching climatic regime. As irrigation cannot always overcome drought conditions, which will become more severe under climate change, to maintain vegetation health, utilities and urban planners should consider the tradeoffs between providing green spaces and water scarcity. This includes evaluating the roles of climate-appropriate landscaping and adaptive reallocation of potable and recycled water resources to enhance water security. By addressing emerging themes in urban water management through analysis of data from forthcoming water metering and aerial imagery technologies, this research provides a unique perspective on water use, greenness, and drought linkages.