A recently published study of the affordability of water services in the United States found that nearly 20 percent of U.S. households have difficulty paying for services related to drinking water and wastewater treatment. The findings come amid growing concerns that water affordability poses an increasing challenge to ever greater numbers of households in the United States.

One day of labor

The study is described in an article, titled “Affordability of household water services across the United States,” that was published May 10 on the website of the journal PLOS Water. The authors were Lauren Patterson, a senior fellow at the Nicholas Institute for Energy, Environment, and Sustainability at Duke University; Sophia Bryson, a former student at Duke University’s Nicholas School of the Environment who is now an environmental scientist at the environmental consulting firm Limno-Tech; and Martin Doyle, the director of the Water Policy Program at the Nicholas Institute for Energy, Environment, and Sustainability and a professor of river science and policy at the Nicholas School of the Environment.

For the purposes of their study, the researchers selected 6,000 gal/mo as the volume of water needed to meet basic needs. This figure is based on an average U.S. indoor per capita water use of 83 gal/d and an assumed 2.4-person household. Hardship was defined as a household spending more than 4.6 percent of its income on water services. 

The 4.6 percent of income “is equivalent to one day of labor for salaried workers,” Patterson says. “You have roughly 22 working days in a month, so each day represents 4.6 percent of income earned in a month.”

Depth versus breadth of burden

The method adopted by the researchers assesses water affordability for all households, rather than evaluating affordability by income level. This approach eliminates the “subjective criteria of selecting a representative household income (e.g., median or 20th percentile household income of the community,” according to the article.

In this way, the study was able to examine affordability in a new light, Patterson says. “Most affordability metrics select a slice of the community to determine if rates are affordable,” she notes. “Historically, this has been the financial burden on the median household income.”

“In more recent years, there has been a push to understand the financial burden for low-income households (20th percentile) and minimum wage earners,” Patterson says. “So we take the representative income of these communities to understand the depth of financial burden. However, we do not know the breadth of households that are financially burdened – i.e., what percent of households spend more than a day each month working to pay for water services.” 

Focus on large utilities

For their study, the researchers examined 787 communities totaling nearly 161 million people, or slightly more than 49 percent of the U.S. population. 

After including all “very large” utilities serving more than 100,000 people, the researchers expanded their study to encompass “all drinking water serving a community with more than 50,000 persons in states with fewer than 10 very large utilities,” according to the article. “If a state still had fewer than ten drinking water utilities represented, we included all utilities serving communities with more than 25,000 persons.”

The researchers determined service boundaries for the selected utilities, obtained rates for drinking water and wastewater services, and calculated the total household water service bills for different volumes of water. Census data were used to determine the population and number of households in each income bracket.

National concern

All told, 17.1 percent of households nationally, accounting for 28.3 million people, were determined to be spending more than 4.6 percent of their income on basic water services. Within the median community, 15.3 percent of households were found to have unaffordable water services, according to the study.

“This research shows that household water unaffordability is not a localized problem but rather is a challenge experienced by households in communities across the nation,” the article states.

What the authors call the “pervasiveness of unaffordability” also varies somewhat regionally, ranging from a low of 11.2 percent in the Southwest to a high of 18.5 in the Mid-Atlantic.

Changing the definition of what constitutes an unaffordable water burden resulted in widely varying outcomes. For example, a financial burden of 2 percent of income resulted in a finding that more than one in three households have difficulty affording water services. On the other hand, raising the financial burden to 7 percent of income reduced the percentage of households experiencing financial hardship to fewer than 1 in 10.

The authors of the study created a data visualization tool that enables users to see how the pervasiveness of unaffordability varies depending on location, water usage volumes, and monthly financial burden.

Because the study focused mainly on urban populations served by large utilities, the results provide a “conservative” estimate of water unaffordability at the household level, according to the article. “If data were included for smaller systems, the proportion of households with water affordability challenges would likely increase rather than decrease,” the article states.