Climate-driven flooding poses well water contamination risks

ST. LOUIS — After a record-setting Midwestern rainstorm that damaged thousands of homes and businesses, Stefanie Johnson’s farmhouse in Blandinsville, Illinois, didn’t have safe drinking water for nearly two months.

Flood water poured into her well, turning the water a muddy brown and forcing Johnson, her husband and their two young children to use store-bought supplies. Even after sediment cleared, testing found bacteria — including E. coli, which can cause diarrhea. The family boiled water for drinking and cooking. The YMCA was a refuge for showers.

“I was pretty strict with the kids,” said Johnson, who works with a private well protection program at the local health department. “I’d pour bottled water on their toothbrushes.”

Though estimates vary, roughly 53 million U.S. residents — about 17% of the population — rely on private wells, according to a study conducted in part by Environmental Protection Agency researchers. Most live in rural areas. But others are in subdivisions near fast-growing metro regions or otherwise beyond the reach of public water pipes.

While many private wells provide safe water, the absence of regulation and treatment afforded by larger municipal systems may expose some users to health risks, from bacteria and viruses to chemicals and lead, studies have found.

Risks are elevated after flooding or heavy rainfall, when animal and human feces, dirt, nutrients such as nitrogen and other contaminants can seep into wells. And experts say the threat is growing as the warming climate fuels more intense rainstorms and stronger and wetter hurricanes.

“Areas that hadn’t been impacted are now. New areas are getting flooded,” said Kelsey Pieper, a Northeastern University professor of environmental engineering. “We know the environment is shifting and we’re playing catchup, trying to increase awareness.”

Pieper is among scientists conducting well testing and education programs in storm-prone areas. After Hurricane Harvey caused widespread flooding along the Texas coast in 2017, sampling of more than 8,800 wells in 44 counties found average E. coli levels nearly three times higher than normal, she said.

Sampling of 108 wells in Mississippi following Hurricane Ida in 2021 produced a similar bump in E. coli readings. Other studies turned up higher levels in North Carolina after Hurricane Florence in 2018.

The following year, above-average snowfall and a March storm unleashed flooding in Nebraska. Levees and dams were breached. Fremont, a city of more than 25,000, turned into an island when the nearby Platte and Elkhorn rivers overflowed.

The municipal system continued to supply drinking water but some nearby private wells were damaged or contaminated. Julie Hindmarsh’s farm was flooded for three days, and it took months to make the well water drinkable again. At times, the cleanup crew wore protective suits.

“They didn’t know what was in that floodwater,” she said.