California Single Family Water Use Efficiency Study

California Department of Water Resources (DWR) | April 20th, 2011

The California Single Family Home Water Use Efficiency Study includes data from many traditional sources such as billing data, survey data, weather data and aerial photo

The California Single Family Home Water Use Efficiency Study includes data from many traditional sources such as billing data, survey data, weather data and aerial photo information to analyze the water use patterns of a sample of over 700 single-family homes across ten water agencies throughout the State of California. Detailed flow trace data was obtained from portable data loggers which were attached to the water meters of each of the study homes. These flow traces provided flow readings at ten second intervals from the magnetic pickup, which generate 80-100 pulses per gallon. These highly detailed flow data make it possible to identify individual water use events and to categorize them by their end-use. The flow trace data tell not just how many gallons per day the home used, but how many gallons per day were used for individual end uses such as toilet flushing, clothes washing, dishwashers, showers, irrigation, faucets and leaks. Detailed use information can be pulled from the trace, giving for example, a count of toilet flushes and toilet flush volumes during a logging period. Researchers used flow trace data to determine levels of daily use in the homes and the efficiency of that use. Although the flow trace technique contains marginal error, such as from the mis-categorization of some events, it provides information on end uses-that is not available from any other source. This report summarizes the results of the study which began in 2005 and was completed in 2010. Water use patterns found during the 2007 logging period were analyzed to show how much potential remains for conservation savings from both indoor and outdoor efforts. 

California’s Next Million Acre-Feet: Saving Water, Energy, and Money

Pacific Institute | September 26th, 2010

A new analysis from the Pacific Institute recommends specific actions that can annually save a million acre-feet of water quickly and at a lower economic and ecological c

A new analysis from the Pacific Institute recommends specific actions that can annually save a million acre-feet of water quickly and at a lower economic and ecological cost than developing new supplies. The assessment notes that new actions are immediately needed to reduce the growing tensions over the state’s water resources and to address California’s persistent water supply challenges. This is a key time for California water: the California Water Bond has been tabled for at least two years and may be scrapped altogether. New reviews from around the state are calling for prompt efforts to use technology, economics, and institutional reform to address the state’s water crisis. All parties seem to agree that the state will need a diverse portfolio of solutions – but it makes the most sense to do the most effective things first. The Pacific Institute’s new report, California’s Next Million Acre-Feet: Saving Water, Energy, and Money, quantifies more than one million acre-feet of water that can be conserved through improved efficiency, with savings coming from the urban and industrial sectors and improvements in agriculture. “There is vast untapped potential to reduce our demand for water without affecting the services and benefits that water provides,” said Heather Cooley, co-director of the Pacific Institute’s Water Program and lead author of the report. “We identified how the next million acre-feet of water can be conserved in California, with approximately 30% of the savings from the urban sector and 70% from the agricultural sector. Both sectors have savings potential far exceeding this amount, and while we could have identified one million acre-feet of water savings annually in either sector alone, we’re showing how all sectors can benefit from these improvements.” In the urban sector, the report identifies water savings from replacing old, inefficient water-using devices with high-efficiency models in our homes and businesses, as well as replacing some lawns with low-water-use plants. In the agricultural sector, best water management practices include weather-based irrigation scheduling, regulated deficit irrigation, and switching from gravity or flood irrigation to sprinkler or drip irrigation systems. The efficiency improvements identified in California’s Next Million Acre-Feet require an upfront investment of less than $1.9 billion, costs that could be borne by a mix of state, federal, and local agencies and individuals – all at a small fraction of the cost of the proposed water bond. The cost of the conserved water is $185 per acre-foot for the agricultural sector and a net savings of $99 per acre-foot for the urban sector, over the lifetime of the efficiency improvement. Conserving water also conserves energy, saves money, and reduces the need for new water and energy projects.

Can water reuse save the Colorado?

University of California, Los Angeles (UCLA) | April 2nd, 2025

To assess the current state of water recycling across the Colorado River Basin and its affected states, UCLA Institute of the Environment and Sustainability, in partnersh

To assess the current state of water recycling across the Colorado River Basin and its affected states, UCLA Institute of the Environment and Sustainability, in partnership with Natural Resources Defense Council, has investigated water recycling progress and policy development across the seven states in the basin.

Carbon Footprint Planning: Quantifying Local and State Mitigation Opportunities for 700 California Cities

Urban Planning (Cogitatio) | April 17th, 2018

Consumption-based greenhouse gas (GHG) emissions inventories have emerged to describe full life cycle contributions of households to climate change at country, st

Consumption-based greenhouse gas (GHG) emissions inventories have emerged to describe full life cycle contributions of households to climate change at country, state and increasingly city scales. Using this approach, how much carbon foot- print abatement potential is within the control of local governments, and which policies hold the most potential to reduce emissions? This study quantifies the potential of local policies and programs to meet aggressive GHG reduction targets using a consumption-based, high geospatial resolution planning model for the state of California. We find that roughly 35% of all carbon footprint abatement potential statewide is from activities at least partially within the control of local governments. The study shows large variation in the size and composition of carbon footprints and abatement opportu- nities by ∼23,000 Census block groups (i.e., neighborhood-scale within cities), 717 cities and 58 counties across the state. These data and companion online tools can help cities better understand priorities to reduce GHGs from a comprehensive, consumption-based perspective, with potential application to the full United States and internationally.

CE2 Model: Evaluating the Costs and Benefits of Urban Water Conservation and Efficiency Measures

Pacific Institute | April 26th, 2012

Over the past 25 years, water conservation and efficiency improvements have provided real water savings, allowing many agencies to maintain or reduce water use while meet

Over the past 25 years, water conservation and efficiency improvements have provided real water savings, allowing many agencies to maintain or reduce water use while meeting the needs of a growing population and economy. Recent studies indicate that despite the improvements that have already been achieved, significant water conservation potential remains. Indeed, California legislation passed in 2009 requires urban water agencies to reduce per capita water use by 20% by the year 2020. The economics of water conservation and efficiency are key issues. The Pacific Institute has developed the Cost Effectiveness of Water Conservation and Efficiency (CE2) Model to help evaluate the economic desirability of water conservation and efficiency measures and explore how costs and benefits can be shared among customers, water utilities, and other entities (system requirements: PC with Microsoft Excel and Access 2003* or later). The model helps document the costs of starting and running a conservation program and estimate the associated water, energy, and financial savings. It is sufficiently general and flexible to address variations in conservation measures regionally and according to the level of analysis because the model outputs are based on conditions defined by the user. The CE2 Model does not provide “the answer” as to whether a particular measure or suite of measures makes economic sense. Rather, it provides a set of financial metrics that can inform the decision-making process. The CE2 Model can also help water conservation practitioners share information across departments and with other water, wastewater, and energy utilities. The model quickly and easily calculates financial metrics that are meaningful and readily understood by planners and managers. It also provides a common platform through which to discuss the costs and benefits of water conservation and efficiency. This in turn allows utilities to exchange cost experiences and data and learn from one another more easily. The primary audience for the CE2 Model is water utility staff. The model is appropriate for wholesale and retail utilities of all sizes and can be used by agencies that exclusively provide water services, as well as agencies that also provide wastewater and/or energy services. Additionally, it may be of use to consultants, non-governmental organizations, and others interested in water conservation and efficiency and sustainable management of water resources.

Changes in water consumption linked to heavy news media coverage of extreme climatic events

American Association for the Advancement of Science (AAAS) | October 25th, 2017

Public awareness of water- and drought-related issues is an important yet relatively unexplored component of water use behavior. To examine this relationship, w

Public awareness of water- and drought-related issues is an important yet relatively unexplored component of water use behavior. To examine this relationship, we first quantified news media coverage of drought in California from 2005 to 2015, a period with two distinct droughts; the later drought received unprecedentedly high media coverage, whereas the earlier drought did not, as the United States was experiencing an economic downturn coinciding with a historic presidential election. Comparing this coverage to Google search frequency confirmed that public attention followed news media trends. We then modeled single-family residential water consumption in 20 service areas in the San Francisco Bay Area during the same period using geospatially explicit data and including news media coverage as a covariate. Model outputs revealed the factors affecting water use for populations of varying demographics. Importantly, the models estimated that an increase of 100 drought-related articles in a bimonthly period was associated with an 11 to 18% reduction in water use. Then, we evaluated high-resolution water consumption data from smart meters, known as advanced metering infrastructure, in one of the previously modeled service areas to evaluate breakpoints in water use trends. Results demonstrated that whereas nonresidential commercial irrigation customers responded to changes in climate, single-family residential customers decreased water use at the fastest rate following heavy drought-related news media coverage. These results highlight the need for water resource planners and decision makers to further consider the importance of effective, internally and externally driven, public awareness and education in water demand behavior and management.

Changing the course? What's worked, what hasn't and what's next for the SCWP: An assessment of the first three rounds of the Safe Clean Water Program

Los Angeles Waterkeeper (LA Waterkeeper) | February 16th, 2023

In 2018, Los Angeles County voters overwhelmingly approved “Measure W” — a 2.5 cent per square foot parcel tax on impervious surface on all land parcels within the

In 2018, Los Angeles County voters overwhelmingly approved “Measure W” — a 2.5 cent per square foot parcel tax on impervious surface on all land parcels within the LA County Flood Control District to fund multi-benefit stormwater infrastructure. The Safe Clean Water Program (SCWP) was developed to distribute and manage the funds raised, approximately $280M annually. The SCWP operates through three distinct programs: the District Program (10% of funds), the Municipal Program (40% of funds), and the Regional Program (50% of funds). The Regional Program has recently completed its third round of funding awarded through a competitive grant process. This assessment focuses on how the Regional Program is performing in achieving the SCWP’s overarching goals of water quality, water supply, and community investment benefits as provided in the ordinance authorizing this measure for the ballot. It also explores how well the program is meeting its goals around community engagement and support, benefits to disadvantaged communities, and green workforce development. The purpose of this assessment is to help the SCWP’s Regional Oversight Committee (ROC) and ultimately other decision-makers such as the LA County Board of Supervisors better understand what is working well with the program and where improvements could be made as part of the biennial review.

Climate Action Plan

Metropolitan Water District of Southern California (MWD) | May 31st, 2022

The Metropolitan Water District of Southern California’s (Metropolitan) core mission is to provide a clean, reliable water supply to Southern California. Changing clim

The Metropolitan Water District of Southern California’s (Metropolitan) core mission is to provide a clean, reliable water supply to Southern California. Changing climatic conditions, variable precipitation patterns, availability of water supplies, changes in consumer demands, and sea level rise will change the way Metropolitan provides its services and how it operates its regional water system. Metropolitan recognizes the potential impact of climate change to water availability and is committed to environmental stewardship to protect this valuable resource. Reducing greenhouse gas (G H G) emissions is an important step in protecting California and the region from the effects of climate change. Reducing G H G emissions from Metropolitan’s operations supports California’s overall G H G reduction goals. This Climate Action Plan (CAP) sets targets for reducing G H G emissions from Metropolitan’s operations, including conveyance, storage, treatment, and delivery of water to its 26 member water agencies. Additionally, this CAP complements Metropolitan’s existing long-range planning efforts, including the Integrated Water Resources Plan, Energy Sustainability Plan, and Capital Investment Plan. Through the implementation of this CAP, Metropolitan will strengthen its commitment to environmental sustainability, increase the resiliency of its operations, and strategically achieve G H G reduction goals. For additional details on the purpose of this CAP and Metropolitan’s history and existing operations, refer to Section 1.0, Purpose, Overview, and Environmental History and Leadership.

Climate Adaptation Master Plan for Water (CAMP4W)

Metropolitan Water District of Southern California (MWD) | March 26th, 2025

To ensure the continued reliability of water supplies for the communities we serve, Metropolitan embarked on the development of a comprehensive Climate Adaptati

To ensure the continued reliability of water supplies for the communities we serve, Metropolitan embarked on the development of a comprehensive Climate Adaptation Master Plan for Water (CAMP4W), a comprehensive set of policy directives and decision-making tools that ensure the Board of Directors is equipped to consider climate risks to water supplies, water quality, infrastructure, operations, workforce, public health, and financial sustainability to its deliberations and investment decisions. It provides a roadmap to guide future investments and decision-making as we confront our new climate reality in the years and decades ahead.

Colorado River Basin August 2022 24-Month Study

U.S. Bureau of Reclamation (USBR) | August 16th, 2022