Data provide snapshot of energy and water demands in U.S. urban environment

Heather Coit

Most of the U.S. population live in urban areas where energy demands exist for distributing drinking water. That energy comes in the form of electricity, natural gas, or fuel oil. But how much water is being consumed and how much energy is needed to collect and treat wastewater? 

Ashlynn Stillwell, assistant professor in the Department of Civil and Environmental Engineering at Illinois, and Christopher Chini, a Ph.D. candidate in the same department, have created a first-of-its kind, publicly-accessible database to answer these questions. 

For their study, which was recently published in Water Resources Research, Stillwell and Chini collected data from over 160 drinking water or wastewater utilities in U.S. cities to find the water demands and their required energy.

“This is a snapshot of the entire United States representing 80 million people for both drinking water and wastewater,” Chini said. 

The researchers found that both energy and water use in urban areas varied drastically throughout the country.

“There really was no regional association for either the amount of energy needed or demand for drinking water, or wastewater from either of these utilities,” Chini said. 

Another important finding involved non-revenue water, which is treated water that never makes it to consumers.  

“We lose one in six gallons of treated drinking water before it even reaches our customers,” Chini said. 

That loss can come from leaky pipes, billing errors, or meter inaccuracies, among other reasons. 

“We really have an inefficiency that is a detriment to water resources and also to the embedded energy in that system,” Chini said. 
Stillwell and Chini found the energy required to treat this water loss annually is enough to power 300,000 homes each year in the United States. 

Stillwell hopes this discovery will highlight the close connection between energy and water, or the energy-water nexus. 

“As consumers of water, we don’t often think about consuming energy while we’re consuming drinking water and generating wastewater, but these two resources go hand in hand,” Stillwell said. “It also shows us that water efficiency is a suitable approach to energy efficiency.”

Stillwell and Chini learned early in their research that studies showing data on water consumption and energy use for that consumption were virtually non-existent. With their open-accessed database, which is being published through HydroShare and hosted by the Consortium of Universities for the Advancement of Hydrologic Science, Inc., they hope to change that.  

Chini plans to promote collaborations between researchers, utilities and governments to collect these data and to expand current knowledge on this important topic.