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 Water Resilience Portfolio

State of California | July 28th, 2020

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.

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.

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-smart management of soil water storage: statewide analysis of California perennial crops

Environmental Research Letters (IOP) | April 9th, 2019

The FAO-56 dual crop coefficient model was used to simulate site-specific irrigation management to quantify the green water resource (rainfall stored in soil) in five Cal

The FAO-56 dual crop coefficient model was used to simulate site-specific irrigation management to quantify the green water resource (rainfall stored in soil) in five California perennial crops (alfalfa, almonds, grapes, pistachios, and walnuts), considering local soil water holding capacity and climate data from 2003 to 2018. We tested different rooting depths and irrigation management thresholds (allowable depletion) across 1.46 million hectares of cropland to determine how the size of the soil water reservoir affects green water utilization and, consequently, blue water demand (irrigation). The 13-year cumulative green water utilization ranged from 17 to 36 million km3 out of a 57 km3 rainfall input and 162–263 km3cumulative blue water demand. For a deep scenario (2 m rooting; 50% allowable depletion), green water met 12% of cumulative crop water demand. However, green water use was not uniform: 20% of the landscape met over 20% of its annual crop water demand. Deeper rooting or greater allowable depletion reduced blue water demand more than the increase in green water utilization, due to less frequent irrigations, which reduced soil evaporative loss. Compared to a 'business-as-usual' shallow irrigation management scenario (0.5 m rooting; 30% allowable depletion), a moderate scenario (1.0 m rooting; 50% allowable depletion) saved 30 km3 blue water evaporation and increased green water use by 7 km3through 13 years. Such savings would fill California's largest reservoir, Shasta Lake, 6.6 times. This study demonstrates an opportunity for climate-smart management of soil water storage, by delayed spring irrigation, applying deeper irrigations less often, and ending fall irrigation early.

Comment Letter on the Draft Water Resilience Portfolio for the State of California

Pacific Institute | February 7th, 2020

This comment letter conveys summary comments and suggestions on the draft Water Resilience Portfolio released by California state agencies, drawing on the considerable ex

This comment letter conveys summary comments and suggestions on the draft Water Resilience Portfolio released by California state agencies, drawing on the considerable experience Pacific Institute has around themes of water efficiency, stormwater management, and the Salton Sea. The letter was authored by staff at Pacific Institute and directed to the Governor’s Water Portfolio Program at the California Natural Resources Agency.

Commercial, Industrial, and Institutional Task Force Water Use Best Management Practices Report to the Legislature

California Department of Water Resources (DWR) | October 21st, 2013

This report to Legislature, Commercial, Industrial, and Institutional Task Force Water Use Best Management Practices, identifies specific practices to improve water use e

This report to Legislature, Commercial, Industrial, and Institutional Task Force Water Use Best Management Practices, identifies specific practices to improve water use efficiency and support California’s water supply sustainability. It is intended to provide the CII sectors with information on water-saving technologies and BMPs applicable in the CII sectors. The report is also intended for use as a resource for: • Existing and new businesses, facilities, and institutions • Developers, consultants, and designers • Water service providers • Planning agencies • Policy makers This two-part document is linked below.  The Executive Summary is also linked in the display window. Executive Summary Volume 1 - A Summary Volume 2 - Technical Information

Comparison of U.S. Geological Survey and Bureau of Reclamation Water-Use Reporting in the Colorado River Basin

U.S. Geological Survey (USGS) | September 2nd, 2019

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State,

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State, and Federal entities develop, compile, and report water-use data, which can lead to confusing or conflicting information. This report was authored jointly by the U.S. Geological Survey (USGS) and Bureau of Reclamation (Reclamation) to compare and contrast the two agencies’ water-use information programs in the Colorado River Basin. The report also describes the legal drivers for each program, clarifies confusing terminol- ogy, compares the methods used, and contrasts the information reported by each agency. This detailed comparison demon- strates that these two Federal agencies have different missions, different programmatic drivers, and different user communi- ties, all of which lead to different approaches to water-use data collection, analysis, and reporting. This report highlights those differences and explains why the USGS and Reclamation programs exist and how the data serve different user communities. Even though the two water-use programs are different by design and purpose, the program comparison presented in this report has identified opportunities for closer coordination and sharing of information between the USGS and Reclamation, as well as program components where agency collaboration can improve water-use estimate methodologies. This comparison effort emphasizes that it is incumbent upon each agency to clearly define the meaning of the terms used and the appropri- ate application of the reported information to avoid confusion or the accidental misuse of the information. An additional benefit of this comparison effort is the formation of a joint USGS/ Reclamation water-use team that will continue to investigate opportunities to expand and coordinate future water-use data compilation and reporting.