When providers act to curtail water use because of a drought, water bills can rise for low-income families while dropping for high-income households, researchers report.

Access to safe, affordable water is a necessity for human health and well-being. But when droughts strike areas that are already water-stressed, water providers are forced to enact measures to curtail water usage or invest in supplies from more expensive sources, which can increase costs for consumers.

According to the new study, these measures can disproportionately affect water bills for low-income households, making water more costly for the most vulnerable people.

“A low-income household often has a different response to curtailment measures and surcharges because of how much water they used before the drought,” says Benjamin Rachunok, who conducted the work as a postdoctoral researcher at Stanford University and is now an assistant professor at North Carolina State University. “This can lead to different affordability outcomes for low- and high-income people, even if the same processes and policies are being applied to everyone.”

The researchers found that in some cases, low-income households end up seeing bills rise during droughts, while high-income households see their bills drop. The work illuminates the interconnected mechanisms that affect affordability and may be able to help water planners and policymakers better understand the potential impacts of long- and short-term drought responses.

When there is a water shortage, providers often ask consumers to cut back on their water usage, while applying a drought surcharge to bills to make up for lost revenue. Fletcher and Rachunok found that high-income households can cut back significantly, lowering their average water bill even with the addition of a surcharge.

Lower-income households, however, tend to have less flexibility in their water usage. Even when they are able to curtail their water use, the drop does not make up for the additional cost of the surcharge.

Water utilities may also invest in infrastructure, such as desalination or water-recycling plants, to increase their water supply. The model showed that in all drought scenarios, these projects increase costs and reduce affordability for low-income households.

Read the full article about droughts and utility bills by Taylor Kubota at Futurity .