Leaks an Untapped Opportunity for Water Savings

Before a drop of treated water in California ever reaches a consumer’s faucet, about 8% of it has already been wasted due to leaks in the delivery system. Nationally, the waste is even higher, at 17%. This represents an untapped opportunity for water savings, according to a study from the University of California, Davis. 

The study, published in the journal Environmental Research Letters, is the first large-scale assessment of utility-level water loss in the United States. It found that leak reduction by utilities can be the most cost-effective tool in an urban water manager’s toolkit, provided utility-specific approaches are used. 

“When I first heard about ‘leaks’ I thought it sounded boring, but leaks are a huge component of our water systems and have a larger opportunity than many other water-saving methods to make an impact,” said lead author Amanda Rupiper, a postdoctoral scholar with the UC Davis Center for Water-Energy Efficiency. “As the first state to regulate its water losses, a lot of eyes are watching California, and this is an opportunity to impact policy here and elsewhere.”

Amid a multiyear drought, the passage of Senate Bill 555 in 2015 made California the first in the nation and among the first in the world to require water utilities to regulate their water losses.

Be Specific

Using data from more than 800 utilities across California, Georgia, Tennessee and Texas, the authors characterized water losses across the country. They developed a model to assess the economically efficient level of losses, and used that model to compare various water loss regulations and modeling approaches.

The study found that one-size-fits-all approaches to leak management are not effective, economical or equitable for utilities, which vary in size and resources. Uniform approaches could lead to the mismanagement of urban water losses. However, applying utility-specific performance standards can deliver a similar amount of water savings at a profit for both utilities and society.

“Regulations that impose a uniform standard across all utilities will result in water reductions that are too stringent in some cases, too relaxed in others, and too costly overall,” the paper concludes.

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UC Davis CWEE Accelerates Water Conservation Research with Secure, Compliant Data Storage on AWS

To solve some of the most pressing water and energy challenges, scientists and engineers need access to robust, reliable data that is often sensitive and protected. Data providers, researchers, and host institutions need to adhere to strict requirements for protecting and securing this data. The Center for Water-Energy Efficiency (CWEE) at the University of California, Davis (UC Davis) used Amazon Web Services (AWS) to create a centralized, secure data repository that streamlines data sharing.

Researchers at CWEE quantify how much energy is used in various elements of the water sector, including potable water, irrigation, and wastewater. This research helps water utilities, energy utilities, and policy makers decide how to invest in and promote water use efficiency, energy efficiency, and electric load shifting in the water sector. This research is critical particularly in California, where drought and other climate change outcomes, like heat waves and forest fires, have been an issue for decades and are growing more severe.

CWEE’s research heavily depends on large amounts of data that must be used in compliance with data privacy requirements. To date, data acquisition has been a largely manual process with strict security agreements and standards that can make it challenging to obtain.

To overcome these challenges, Dr. Frank Loge, director of CWEE and a professor in the UC Davis Civil and Environmental Engineering department, worked with UC Davis’s information technology departments to develop a new secure, shared system using a range of AWS services. The new system protects sensitive research data, makes clear who is responsible for protecting it, and verifies compliance. The system has garnered new interest and funding opportunities and has the potential to help spur new innovations in the water sector, driven by broad access to data.

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How Water Conservation can Help Save Energy, Too

Watering the lawn less, taking shorter showers, and switching to a low-flow toilet all conserve water. And they also reduce carbon pollution. “About 20% of the state of California’s energy use is associated with the water system,” says Frank Loge of the University of California, Davis.

He explains that every step of a water system uses energy: pumping water from lakes and reservoirs, treating it to make it safe to drink, and pumping it into homes and businesses. Then, if it’s sent down a sink or toilet, it’s usually processed at a wastewater treatment plant, which Loge says takes a tremendous amount of energy.

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Evaluating Water Loss Performance Standards – An Economic Leak Loss Reduction Model

The UC Davis Center for Water-Energy Efficiency (CWEE) developed an economic optimal leak loss model and performed a study using water utility data from four different states to evaluate the results of the CWEE model and others* (including the State Water Board’s current model). CWEE recently performed a similar assessment tailored for California by comparing economic models using California utility data only. Attend this public webinar to learn about the UC Davis Economic Optimum model and how it compares to the proposed California model.

The purpose of this webinar is to inform stakeholders in the water loss space about the findings of CWEE’s research. This topic is relevant to California utilities and policy makers and will provide data driven science for stakeholders to consider during the upcoming Water Loss Performance Standards rulemaking by the SWRCB. This webinar will be followed up by 1-2 shorter webinars open to the public to provide more in-depth question and answer sessions.


* This work is currently in the peer-reviewed publication process. Learn more about the study and review a related publication here: https://cwee.ucdavis.edu/research/economic-leak-loss-model/


  • Amanda Rupiper, Postdoctoral Scholar, Department of Civil and Environmental Engineering, UC Davis
  • Katrina Jessoe, Associate Professor, Department of Agricultural and Resource Economics, UC Davis
  • Ellen Bruno, Assistant Cooperative Extension Specialist, UC Berkeley
  • Frank Loge, Professor, Department of Civil and Environmental Engineering, UC Davis

Please reach out to Kendra Olmos at kcolmos@ucdavis.edu for additional information about this webinar.

Is California Ready for Brown Lawns and Shorter Showers? Drought Requires Less Water Use

In the face of rapidly worsening drought conditions this week, Gov. Gavin Newsom urged all Californians to voluntarily cut their water usage by 15% — but what exactly does that mean for the average California household?

The governor made his plea Thursday as he extended a regional state of drought emergency to 50 counties, comprising about 42% of the state’s population. For many, the talk of water reductions reminded them of the shriveled lawns, attenuated showers and water-bucket toilet flushing of the last devastating drought.

It also prompted some to wonder just how much more water Californians can conserve, since they continue to use substantially less water than they did before the 2012-2016 drought.

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U.S. West faces little-known effect of raging wildfires: contaminated water

Early this spring, water bills arrived with notes urging Fort Collins Utilities customers to conserve. The Colorado customers may have thought the issue was persistent drought in the U.S. West.

But the problem was not the quantity of water available. It was the quality.

Utilities are increasingly paying attention to a little-known impact of large-scale fires: water contamination.

Huge forest fires last year denuded vast areas of Colorado’s mountains and left them covered in ash – ash that with sediment has since been washed by rains into the Cache la Poudre River. The river is one of two sources for household water in this college town of 165,000. With more and fiercer storms expected this year, officials worry about water quality worsening beyond what treatment systems can handle.

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Estimating Agricultural Groundwater Withdrawals with Energy Data

Agricultural water use is the leading cause of groundwater overdraft in California. However, agencies tasked with managing groundwater resources do not have access to accurate and reliable measurements of groundwater extraction. Previous studies identified a relationship between pump energy consumption and groundwater extraction and indicated that the efficiency lift method (ELM) can produce reliable estimates of groundwater extraction if based on reliable data. Recent advances in the availability of electricity and pump operating condition data have made the ELM viable for estimating large-scale groundwater extraction. This study considered the feasibility of using the ELM to estimate groundwater extractions from both individual wells and larger areas and identified the best data sources available for such estimates. Researchers found mean error rates of 5% at the individual well level and 3.3% for collections of wells when using the most specific data sources available, such as pump test reports and spatial groundwater level datasets. This research suggests that the ELM is a reasonable approach for estimating groundwater extraction on a large scale.

Visit the Journal of Water Resources Planning and Management to read the full article.


Saving Water Saves Energy and Reduces Greenhouse Gas Emissions

Conserving water goes beyond just saving water; it plays a vital role in conserving energy and reducing greenhouse gas emissions (GHGs). This is one of the main conclusions of a landmark study conducted by UC Davis in collaboration with the Los Angeles Department of Water and Power (LADWP).

The study, published in the journal Environmental Research Letters, shows that customer-focused water conservation programs are just as cost-effective (and in some cases, are more cost-effective) as energy efficiency programs in reducing electricity use, GHGs and other energy-intensive operations.

“In California we use about 20% of statewide electricity and 30% of non-power plant natural gas to move, treat, and heat water,” said author Edward Spang, an assistant professor in the UC Davis Food Science and Technology Department and the Center for Water-Energy Efficiency. “Using LADWP as a case study, we wanted to examine the energy savings secured through water conservation programs relative to energy efficiency programs.”

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Spillovers from Behavioral Interventions: Experimental Evidence from Water and Energy Use

This paper provides experimental evidence that behavioral interventions spill over to untreated sectors by altering consumer choice. We use a randomized controlled trial and high-frequency data to test the effect of social norms messaging about residential water use on electricity consumption. Messaging appears to induce a small reduction in summertime electricity use. Empirical tests and household survey data support the hypothesis that this nudge alters electricity choices. An engineering simulation suggests that complementarities between appliances that use water and electricity explain roughly a quarter of the electricity reduction. Incorporating the cross-sectoral spillover increases the net benefits of the intervention substantially.

Read the paper in the Journal of the Association of Environmental and Resource Economists

The Cost-Effectiveness of Energy Savings Through Water Conservation: a Utility-Scale Assessment

It is well-established that water infrastructure systems require energy to treat and deliver water to end-users. This fundamental relationship presents an opportunity to secure energy savings through water conservation. In a previous study, the energy savings linked to a statewide water conservation mandate in California were found comparable in both resource savings as well as cost-effectiveness to the energy savings achieved directly through energy efficiency programs. This study pursues a similar line of inquiry, but at the scale of an individual city as opposed to a statewide assessment. Los Angeles, California, serves as the case study for estimating the energy savings secured through water conservation programs relative to energy efficiency (EE) programs enacted in the study region. We apply three different estimates of energy intensity (EI) for the conversion of water savings to energy savings. These applied EI scenarios are differentiated by scale and system boundary, including: a direct assessment of EI within the water utility service territory, an expanded boundary that includes imported water infrastructure systems, and a broader, top-down estimate for the regional hydrologic zone. Across all scenarios, the estimated energy savings secured through water conservation programs prove to be cost-competitive with the energy efficiency programs enacted by the utility. When using estimates of EI with expanded system boundaries that include the upstream energy embedded in imported water supplies, water conservation becomes a significantly more attractive pathway for saving energy. This outcome underlines the importance of clearly defining the water-energy system boundary of interest, both to determine an accurate EI value, and subsequently, to design and implement cost-effective programs that jointly conserve both water and energy resources.

Read the article in Environmental Research Letters

Load Shifting at Wastewater Treatment Plants: A Case Study for Participating as an Energy Demand Resource

Energy load shifting can allow for increased renewable energy integration and reduced greenhouse gas intensity of the electricity grid. Recent research has demonstrated that wastewater treatment plants have considerable potential to shift energy loads and act as energy demand resources due to their energetic flexibility and energy production capacity. This paper investigates a wastewater treatment plant in Santa Rosa, California, participating as a demand resource on the wholesale energy market through the proxy demand resource program. Test demand response events showed that the facility was able to shift its energy load by modifying select operations without impacting wastewater effluent quality. A cost-benefit analysis based on projected program participation and the results from the test events, estimates that the Santa Rosa wastewater treatment plant could achieve up to 4.8% energy cost savings through the proxy demand resource program. Two main issues were identified from the test events: (1) the difficulty of correctly timing demand reduction periods and (2) the inaccuracy of using standard baseline methods to measure the energy load reduction. As a supplement to the case study, this paper also presents a roadmap outlining the technology necessary for wastewater treatment plants to participate in demand resource programs through energy load shifting. The roadmap identifies key instrumentation and automation infrastructure, and assets that can be utilized to provide energetic flexibility; it also recommends additional infrastructure that can stabilize energy loads and enhance controlled energy load shifting.

Read the article in the Journal of Cleaner Production