Water utility doing tests to figure out well contamination

Sodium levels increasing in Well 14
Water utility doing tests to figure out well contamination

The Madison Water Utility shut down a west side well for four weeks in order to figure out why sodium and chloride keep making their way into the well.

Well 14, which is just west of University Avenue, provides more than 750 million gallons of water every year to west side residents. But in the past five years, the water has started to taste different.

“They’d say, ‘The water used to taste great, and now it tastes different. It’s not as good,'” recalls Marie VanAartsen, who answers calls to the utility’s water quality line. “They couldn’t always pinpoint what was different. Just that it was different. It was more residents who had lived in the neighborhood for a long time, 20 or 30 years. This was their consistent source of water, and they could notice a change, not so much day-to-day, but from in the past.”

So, the utility decided to shut down the well for a few weeks to try and determine what is going on. The utility is working with the Wisconsin Geological and Natural History Survey to do tests on what might be causing the possible contamination.

“We want to see if there’s anything we can do to improve water quality by potentially rehabbing the well. Before we make any decisions about rehabilitation, we really have to better understand the geology, better understand where the water’s coming from and the water quality characteristics of that well,” says Joe Grande, who heads up the utility’s water quality department.

Workers have started lowering probes into the 700-foot bore hole beneath the well to look at everything going on. They hope to try and figure out what geological formations might be leading to the sodium and chloride contamination in the well.

“We’re trying to get at where the sodium and chloride are potentially coming from, where in the bore hole. Is there something that we can do to seal off portions of the bore hole to improve water quality? By having that information and knowing which portions of the well are the most productive in terms of water supply, we can find out.”

Utility officials said the water pumped out of the well is about 16 years away from crossing an EPA-recommended threshold for chloride.

Officials have also encouraged residents near the well to limit their use of road salt on driveways and parking lots. Officials believe use of salt is one of the reasons for the increased levels of sodium and chloride in the well.

Madison Water Utility said they may receive results of the study in a few months.

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