Pacific Institute Develops Water-Energy-Climate Calculator


Paula Luu Guest Blog

By Paula Luu, Communications Associate for the Pacific Institute

Reposted from the California Sustainability Alliance:

See also Peter Gleick's blog about WECalc.

There are tremendous opportunities to improve efficiency of household water use without affecting the services and benefits that water provides—and to reduce energy use and greenhouse gas emissions at the same time. Researchers at the Pacific Institute have developed WECalc ("Your Home Water-Energy-Climate Calculator"), a free online tool that empowers users with information on their water and related energy use and identifies strategies to reduce them.


WECalc asks users a series of questions about their personal water use habits and, based on their responses, estimates total water use and provides personalized recommendations for reducing that use. WECalc also helps users have a better understanding of the connections between water and energy by providing them with an estimate of their water-related energy use and associated greenhouse gas emissions.


Numerous studies show that the water conservation potential is substantial and largely untapped. Existing, cost-effective technologies can reduce household water demand by 30 to 40 percent, and the good news is that these currently available water-efficient technologies can help homes and businesses save water without sacrificing their quality of life. In fact, most homeowners believe that the performance, maintenance, and appearance of the efficient appliances are superior to older appliances.

Water is both heavy and extremely energy intensive to heat. As a result, capturing, treating, moving, and using water requires large amounts of energy. This is particularly true in the West, where water supplies and population centers are often separated by hundreds of miles. In California, for instance, an estimated 19 percent of electricity use, 32 percent of all natural gas consumption, and 88 million gallons of diesel fuel consumption are water-related. To put these numbers in perspective, consider that leaving the hot water running for five minutes uses as much energy as operating a 60-watt light bulb for 14 hours! While California’s water supplies may be more energy-intensive than the national average due to the particularly long distances and elevation changes during water transport, about 80% of California’s water-related energy use is due to customer end-use, for example, the energy required to pressurize or heat water prior to use. Since end-use energy requirements are similar across the United States, it is likely that water-related energy use is high across the country.

This means that saving water also saves energy and reduces greenhouse gas emissions. The California Energy Commission found that it is cheaper to save energy through water-efficiency improvements than through traditional energy-efficiency measures. American households can save water, energy, and money by implementing widely available, cost-effective technologies. Tools like WECalc provide the user with information to begin realizing those savings.


“When you account for all the other benefits that flow from saving water—like lower energy bills, reduced landscaping costs, and the reduction in wastewater—water efficiency measures become very cost-effective,” said Heather Cooley, co-director of the Pacific Institute’s Water Program and one of the creators of WECalc. “The Pacific Institute has conducted economic analyses in recent years that show that myths and misunderstanding —not economics—are the biggest barriers to improving our water use efficiency. We developed WECalc as an easy-to-use public outreach and education tool that brings water and energy savings home.”

The potential water and energy savings currently available nationwide are immense. WECalc makes suggestions for simple installations and behavioral changes which can offer substantial water and energy bill savings for users too. Simple actions, like installing a faucet aerator, cost only $1 to $4 but save $47 per year and reduce carbon emissions by about 310 pounds per year. Cutting down shower time by one minute is a no-cost way to save over 100 pounds of carbon per year.

“The researchers spent a lot of time sweating even the smallest details,” said Bevan Griffiths-Sattenspiel of River Network. “For the layperson, just about every question in the calculator has a link that leads the user to helpful tips, definitions, or explanations of why the question is important, while for those wonks out there, the tool’s assumptions and sources are all meticulously documented so you can see just how scientifically sound the model is.”

Individual actions matter: even choices of water-using appliances have a big impact on water and energy use. As water and energy managers—and individualslook at the benefits and connections with water conservation and improvements in efficient water use, WECalc is a key tool for seeing how reducing water use helps us meet greenhouse gas targets and reduce carbon footprints. Water agencies and municipalities can encourage use of the water-energy calculator as an educational tool to allow consumers the ability to examine the greenhouse-gas emission reductions associated with water conservation and efficiency improvements. WECalc allows users to analyze their water use and make informed decisions about how to conserve water. The bottom line is that saving water saves energy and reduces greenhouse gas emissions, a win for our environment, and a win for consumers.


The Pacific Institute is one of the world’s leading non-profit research and policy organizations working to create a healthier planet and sustainable communities. Based in Oakland, California, we conduct interdisciplinary research and partner with stakeholders to produce solutions that advance environmental protection, economic development, and social equity—in California, nationally, and internationally.