Residents in the village of Williams Bay are again able to drink tap water after nitrite contamination warranted a “Do Not Drink” order from the Wisconsin Department of Natural Resources for over a week.
In late August, the DNR issued the order for residents of the village of nearly 3,000 to stop drinking and cooking with public water due to positive tests of nitrites in the system. Nitrites are a natural part of the life cycle but can lead to serious health concerns, especially for babies, when consumed in large quantities.
On Friday, the DNR lifted the order after tests showed water quality returned to safe levels.
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Steve Elmore is bureau director of the DNR’s Drinking Water and Groundwater Program. He recently told WPR’s “Wisconsin Today” that the Williams Bay case is a bit unusual compared to how nitrates and nitrites typically contaminate drinking water.
“We usually are not concerned about nitrites or nitrates in public water systems,” Elmore said. “I mean, it’s something they test for at the wells before the water goes out to the distribution system and we monitor those results regularly. … But what we were concerned about and what indeed was happening was nitrites were actually being created in the distribution system.”
Elmore said the unusual case of nitrites in Williams Bay happened because the water pulled from wells contained the chemical ammonia. And while the levels of ammonia are not concerning to the public, its presence meant bacteria in the pipes could eat the ammonia and produce nitrites.
To solve the problem, Elmore said the utility added extra chlorine to the system to eliminate the bacteria in the pipes and “slow down” the bacteria’s process of converting ammonia to nitrites.
“And I say slow down because it’s still going to be a factor, and it’s something that they’re going to have to manage because there is ammonia in their source water,” he said.
While it might sound alarming to hear about bacteria growing in water pipes, Elmore said it’s typically not a cause for concern. He said the bacteria usually grow in small numbers and that the types of bacteria are often the same kinds that people would find living within their own bodies.
“They’re harmless to us, but they are causing reactions in the water pipes themselves, negative reactions that we need to reduce and eliminate, if possible,” Elmore said.
Nitrates can be problematic for private drinking wells
Nitrates, a closely related chemical to nitrites, can often be a problem for private drinking wells across the state. Sara Walling is water and agriculture program director for the advocacy group Clean Wisconsin. She said nitrate contamination around the state typically comes from large agricultural runoff.
About 90 percent of all nitrate-contaminated groundwater is due to agriculture, according to Clean Wisconsin.
“(Nitrates and nitrites are) by far our state’s and nation’s most widespread groundwater contaminant,” Walling said. “About 5-10 percent of (private wells) across the state have nitrate levels above what we call the maximum contaminant level, which is 10 parts per million. And that’s a level that triggers some action because there are health implications at that level.”
Walling added that another 15 to 25 percent of private wells in the state have elevated levels above 5 parts per million, which, at those levels, could potentially still cause health problems. She said nitrate contamination in wells is twice as common in areas with widespread agricultural use, typically southcentral, central and western parts of Wisconsin.
Walling said her goal is to get state assistance in incentivizing all Wisconsin farmers to develop nutrient management plans to reduce overusing fertilizers that can lead to nitrate runoff. She said the state has to step in and offer cost-sharing for farmers to be able to develop such plans.
“One of the main triggers is: There is a cost to this, and there often isn’t a lot of technical assistance available to help farmers really understand how to best balance nutrient need with crop needs so that there isn’t as much available in the system to leach out to groundwater,” she said.
Walling said that while there are state programs to help offset the cost to homeowners of digging new wells or putting in filtration systems, they can often have “restrictive eligibility requirements,” making it difficult to access for many would-be applicants.
“There are some pretty low-hanging fruit policy changes that could be made to at least ensure that those homeowners who find high levels of nitrates in their wells could have access to funding,” she said. “And we’re certainly going to be working with our state Senate and Assembly to advance policy changes to achieve that.”
