Water well near campus reaches contamination threshold

A well that pumps more than 750 million gallons of water near the UW-Madison campus has reached a “critical contamination threshold” of sodium and chloride due to road salt, with chloride levels doubling since 2000.

The Madison Water Utility is launching a multi-year study of Utility Well 14 in response to explore ways to mitigate road salt contamination. That study will start by analyzing the hole of the 56-year-old well to determine which areas below ground are contributing the most sodium chloride, according to a city press release.

“From there, the utility will look at every available option,” Madison Water Utility Public Information Officer Amy Barrilleaux said. “From rebuilding part of the well in order to draw water from deeper in the aquifer to on-site desalination treatment to abandoning the well entirely.”

The chemicals in themselves are not considered dangerous to most people, however the current sodium level is at 45 mg/L. That level is more than double the EPA-recommended level for people with high blood pressure. If the current trend continues, the water from the well may be so salty in 17 years that it would be undrinkable.

According to city Water Quality Reports, Well 14 is one of four wells that serve campus. Well 6, which also serves part of campus and the Regent and Greenbush neighborhoods, has shown increased levels of sodium and chloride. However, the levels are not close to those of Well 14. In addition, Well 6 is a seasonal well that typically operates in summer months only.

“Rising levels of chloride in our groundwater and lakes should be a cause of concern to all of us,” Madison Water Utility general manager Tom Heikkinen said in a statement. “As a region, we are on an unsustainable path with respect to wintertime salt use and we need to figure out how to solve this problem now for the sake of future generations.”

Madison Water Utility Water Quality Manager Joe Grande said he hopes homeowners and renters, in addition to municipalities, will be more conscious of their salt usage.

“We’re not saying don’t use salt because we think public safety is important, but we are trying to advocate for smarter and wiser use of salt,” Grande said.

According to the city, road salt washes toward Well 14, which is in the Spring Harbor neighborhood, from as far as West Towne Mall. Even if all road salt distribution stopped immediately, there is enough sodium chloride in the ground that levels would likely continue to rise.

“Well 14 really is a warning to the Water Utility and to the community that road salt application does have impacts on groundwater and on surface water. We see it in the lakes as well,” Grande said.