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Study: Maine Among States with Most Corrosive Groundwater


According to a new study by the U.S. Geological Survey, Maine is one of 11 states that has the highest prevalence of potentially corrosive groundwater, which can leach heavy metals like lead from old plumbing and fixtures. And that means more than half a million Mainers who rely on private wells should get their water tested.

On its own, corrosive groundwater isn’t necessarily bad, says Joe Ayotte of the USGS. It has a low pH, meaning it’s acidic.

“Low pH in general is not particularly harmful,” he says. “A lot of the things that we drink are low in pH. Think about lemonade.”

But you might not want to drink that lemonade if it came to your glass through old pipes and fixtures. Because when corrosive groundwater passes through old plumbing, it can leach out heavy metals like lead.

Ingesting lead can cause neurological and other health problems. Given the health risks, the USGS studied groundwater corrosivity across the U.S. Ayotte says half of all states have a high prevalence of potentially corrosive groundwater, and 11, including Maine, have a very high prevalence.

“Maine, New Hampshire, Massachusetts, basically all of New England, maybe with the exception of Vermont, has the highest potential,” he says.

Those who should be most concerned are people with private wells. That’s because public water systems are regulated and water is often treated to control corrosion, but private wells are unregulated. For the more than 500,000 people in Maine who depend on well water, it’s up to the owner to make sure the water is safe.

“For private wells, private domestic wells, people really need to have their water tested. It always comes back to that,” Ayotte says.

The problem is many private well owners don’t test their water, says Emma Halas O’Connor of the Environmental Health Strategy Center.

“That’s really not working when it comes to arsenic, which the Maine CDC has kept track of,” she says. “We know that only about 45 percent of people on well water are testing their water for arsenic.”

In 2010, a different USGS study found about 1 in 10 wells in Maine have arsenic above federal standards. Arsenic has been linked to certain cancers as well as developmental disabilities.

O’Connor says the state needs to do more outreach and education.

“You have to actually know to order a comprehensive water test in order for arsenic and lead to be tested,” she says. “Those are not chemical contaminants that are part of the standard drinking water test.”

Gov. Paul LePage vetoed a bill last year that would have expanded outreach and education on well water testing. The LePage administration also failed to reapply for a federal grant to support similar efforts.

In an email, a Maine CDC spokesman recommends well owners who suspect their water is corrosive test for lead and copper.