Climate-induced flooding poses well water contamination risks |

ST. LOUIS — After a record-breaking Midwest rainstorm that damaged thousands of homes and businesses, Stefanie Johnson’s farm in Blandinsville, Illinois, had no clean water for nearly two months. .

Floodwater poured into her well, turning the water muddy brown and forcing Johnson, her husband and their two young children to use store-bought supplies. Even after removing the sediment, tests found bacteria, including E. coli, that can cause diarrhea. The family boiled water for drinking and cooking. The YMCA was a haven 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 would pour bottled water on their toothbrushes.”

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

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While many private wells provide safe water, the lack of regulation and treatment offered by large municipal systems can expose some users to health risks, from bacteria and viruses to chemicals and lead, according to studies.

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

“Areas that had not been affected are affected now. New areas are flooding,” said Kelsey Pieper, professor of environmental engineering at Northeastern University. “We know the environment is changing and we’re trying to catch up, trying to raise awareness.”

Pieper is among the 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 revealed average levels of E. coli nearly three times higher than normal, she said.

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

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

The municipal system continued to provide 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. Sometimes the cleaning crew wore protective suits.

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

Groundwater is often a cleaner source than surface supplies because soil can provide a protective buffer, said Heather Murphy, an epidemiologist at the University of Guelph in Canada. But she said it can give well owners a false sense of security, leading them to forego testing, maintenance and treatment.

“There’s a big misconception that it’s underground, so it’s safe,” said Murphy, who estimates that 1.3 million cases of acute gastrointestinal illness in the United States are caused each year by consumption of untreated water from private wells.

Old, poorly maintained wells are particularly vulnerable to floodwater entering through openings at the top. “It just sinks in and it’s full of bacteria,” said Steven Wilson, a sink expert at the University of Illinois.

It doesn’t always take a flood or a hurricane to pollute wells. Industrial contamination can reach them by seeping into groundwater.

While many well owners do not have the option of hooking up to a public water system, others are happy with well water. They might favor taste or want to avoid monthly bills and government regulations.

“What I hear from people is freedom,” said Jesse Campbell, private well coordinator for the Midwest Assistance Program Inc., which serves rural water needs.

Owners of private wells are responsible for this. Although public water supply systems must meet federal safety standards, these rules do not apply to wells that have fewer than 15 connections or serve fewer than 25 people.

Even ordinary thunderstorms can carry disease into groundwater, said Mark Borchardt, a microbiologist formerly with the US Department of Agriculture.

“A lot of times people say, ‘Well, nobody got sick,'” Borchardt said. “It’s hard to see when people are getting sick unless it’s a huge outbreak.”