People May Get Sick More Often From Untreated Drinking Water Due To Climate Change

State and federal laws set drinking water standards to protect public health. Wisconsin residents on municipal systems may think that means their water is always safe to drink. But, researchers say viruses are finding their way into water sources undetected and climate change may only make matters worse.

A city well in Washburn pumps 323 gallons of water every minute up the hill to the city’s reservoir, said city water operator Ross Lightner. Washburn has two wells that provide drinking water to about 900 households. The city is among 56 municipal water utilities statewide that don’t regularly disinfect their drinking water, according to the Wisconsin Department of Natural Resources.

But Lightner said the city meets state standards by testing for total coliform bacteria.

“We meet our bacterial levels without having to disinfect,” he said. “We test three times a month required by the DNR.”

The tests reveal any problems that may exist in a drinking water system or well. If tests don’t reveal anything, Lightner said there’s no need to disinfect.

“The Wisconsin DNR is telling us that we don’t have to so if we don’t have to chlorinate our water, it’s kind of a ‘why would you’ kind of thing,” he explained.

Makes sense, but Chris Uejio thinks they should disinfect. Uejio, an assistant geography professor at Florida State University, has been researching the link between rainfall and illness. His most recent study was published in January in the Hydrogeology Journal.

Uejio studied the rate of stomach illness among children in northern Wisconsin communities that do and don’t disinfect their drinking water.

“In these areas where they were treating their drinking water, we did not find any systematic relationship between rainfall and new human illnesses,” he said. “But, we did find a pretty systematic and consistent relationship in these communities in northern Wisconsin that were accessing municipal water that was untreated.”

Simply put, rain is transporting viruses that make people sick into drinking water sources. Using climate models, Uejio’s study shows young children or other at-risk groups in those communities will be more likely to fall ill from untreated drinking water as the area sees more frequent, intense rainfall due to climate change.

“We found a pretty modest increase due to climate change,” he said.

That increase ranged anywhere from a 1- to 2-percent increase in the rate of gastrointestinal illnesses.

Wisconsin Geological Survey hydrogeologist Madeline Gotkowitz said communities that don’t treat their water aren’t doing anything wrong. They’re just following state standards.

“But, the way a lot of people interpret that is if their well passes the total coliform test then the water must be safe to drink,” she said.

But, those tests don’t look for the presence of viruses that Uejio said are making people sick.

“For a long time, myself included, I didn’t understand that pathogens could be transported great distances in groundwater systems,” said Gotkowitz. “I thought they were filtered out by sand and aquifer solids.”

U.S. Department of Agricultural research service microbiologist Mark Borchardt said research showed pathogens could penetrate layers of rock thought to filter out contamination in a study of enteric viruses in Madison drinking water wells that was published in 2007.

“When it rains, people should understand that’s when contamination happens … So many people have this view of groundwater being ancient and deep and coming from an underground river,” Borchardt said. “Actually, a lot of it’s just rain that fell in the ground two weeks earlier.”

Several years ago, the findings swayed the Wisconsin DNR to revise its drinking water rules so that all municipal water utilities would have to disinfect. But, the state Legislature nixed that requirement in 2011. Opponents argued local governments should decide whether to treat their water. They pointed to added costs for cash-strapped communities and even taste.

Washburn City Administrator Scott Kluver said they have received quite a few complaints from residents when they’ve had to disinfect their drinking water.

“There’s usually a line of people trying to fill up water at the artesian well because they don’t like the smell or the taste of chlorine,” said Kluver.

But, Uejio said his study found that treating drinking water would prevent 82 percent of stomach illnesses associated with rainfall in communities that don’t regularly disinfect. As Wisconsin sees hotter, wetter weather, those communities may see residents lining up more often at the doctor’s office instead and paying more out-of-pocket to treat illnesses that could have been prevented.

This story is part of a yearlong reporting project at WPR called State of Change: Water, Food, and the Future of Wisconsin. Find stories on Morning Edition, All Things Considered, The Ideas Network and online.