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DAWS well water quality testing results released
In Crawford and Vernon counties
November 2022 DAWS nitrate results
THE MAP above depicts the nitrate results from the Driftless Area Water Study (DAWS) well water testing event conducted in November of 2022 in Crawford and Vernon counties. Nitrate levels of 2.0 or below are considered to be ‘naturally occurring,’ and levels above 10 mg/L are considered to mean the water is unsafe to drink.

CRAWFORD/VERNON COUNTIES - The most recent round of Driftless Area Water Study (DAWS) well water quality testing results were released on Tuesday, Jan. 10.  Kevin Masarik, watershed educator with the Center for Watershed Science and Education (CWSE) at UW-Stevens Point made the presentation.

The results are from 29 tests in Crawford County, 25 tests in the Tainter Creek Watershed, and 53 tests in Vernon County. Richland County, a historic partner in the DAWS Study, did not participate in this round of testing due to budget constraints.

The Tainter Creek Watershed starts in Franklin Township in Vernon County, and runs through Utica Township in Crawford County, with the creek’s confluence ar the Kickapoo River occurring just north of the Village of Gays Mills.

Of the total 107 wells tested, approximately 11 tested in the 10.1-20 milligrams-per-liter (mg/L) of nitrate range. The health standard for nitrate in drinking water is 10 mg/L. Above this level, water is not considered safe for drinking.

Twenty-one of the 107 wells tested in the 5.1-10 mg/L range for nitrate. While still considered safe to drink, this is considered to be the ‘danger zone’ where well owners should investigate why nitrate levels in their water are elevated, and consider repeated testing to determine if levels are increasing.

Vernon County Public Health Department (VCPH) in Viroqua offers well water nitrate testing for a cost of $30 per test. Bottles can be picked up at the VCPH Department offices at 318 Fairlane Drive in Viroqua between the hours of Monday-Friday, 8:30 a.m. to 4 p.m. Return samples are accepted Monday-Thursday, from 8:30 a.m. to 4 p.m., and results will be available in one-to-two weeks.

Twenty-four well tests of the 107 tested came back in the 2.1-5 mg/L range. This water is safe to drink, but again, the cause of nitrate contamination should be investigated, and well owners are encouraged to re-test their well water.

Thirty-two wells of the 107 tested came back at the 2.0 mg/L level, which is considered to be the naturally occurring level of nitrate in groundwater without human influence. Two wells of the 107 tested came back with a result of no nitrate present.

Hard water

Generally, in an area like the Driftless Region in Southwest Wisconsin, the karst geology bedrock composed of sandstone and dolomites will deliver very hard water. This water will be high in minerals like calcium and magnesium, which in normal levels are not considered to be harmful and may have health benefits.

The main issue with hard water is scaling and scum. The water can require higher levels of soaps for cleaning and laundry, and it can decrease water heater efficiency.

Results for hardness above 200 mg/L are considered to be ‘hard water.’ In Crawford County, one well tested at 401 mg/L, and in Vernon County, four wells tested at this level. In the 301-400 mg/L level, 19 wells in Crawford County and 31 wells in Vernon County tested at this level. In Crawford County, 11 wells tested at the 201-300 mg/L level, and in Vernon County, 18 wells tested at this level.

In the 101-200 mg/L, no Crawford County wells tested at this level, and four Vernon County wells did. At the 51-100 mg/L level, no wells in either county tested at this level. One well in Vernon County tested at the 50 mg/L or less level in the far eastern part of the county.

Bacteria levels

In the combined Crawford and Vernon counties, and the Tainter Creek Watershed, of the total 105 wells sampled, 16 percent of the samples analyzed detected coliform bacteria.  There was one sample (less that one percent of all samples) that detected E.coli. The results for coliform bacteria and E.coli are both on par with statewide averages. 

Masarik pointed out that generally, coliform bacteria in well water do not cause illness. However, he pointed out that their presence in well water can indicate that a pathway for potentially harmful microorganisms to enter your water supply exists.

Harmful bacteria, such as E.coli or viruses have the potential to cause gastrointestinal disease, cholera and hepatitis. Wisconsin’s well code stipulates that “a properly constructed well should be able to provide bacteria-free water continuously, without the need for treatment.”

“If your well tested positive for E.coli, a dangerous pathogen that comes from human or animal fecal matter, you would have been notified immediately. E.coli in water are often present with harmful bacteria, viruses and parasites that can cause serious gastrointestinal illnesses, and water should ceased to be consumed immediately if E.coli are found to be present,” Masarik said. “If your well tested positive for coliform bacteria, we recommend further testing to determine if bacteria are persistent in the well, and require further action.”

Masarik detailed that sources of coliform bacteria in well water include naturally occurring levels in soils and on vegetation, human or animal waste, or could show up in the test results due to a sampling error.


Well owners whose wells test positive for coliform bacteria need to become ‘investigators,’ to determine what the possible sources or causes of bacteria in their well water might be. While public water systems are highly regulated, and required to test regularly, private well owners are essentially their own water utility managers.

Issues that have potential to create pathways for bacteria into well water include land use in the neighborhood of the well, and well construction defects. Well construction defects can include damaged well caps, and lack of adequate casing. Bad well water can also result from old wells on the property that haven’t been capped, inadvisable land use around the well head, or failure to control backflow in hoses attached to the well.

“Well owners whose wells test positive for coliform bacteria should inspect their well head and the area around the well,” Masarik said. “First, see if the cap on your well head or casing is cracked, then determine if the cap is a vermin-proof cap.”

Masarik said that if there are old wells on the same property that have not been properly filled and capped, they could be functioning as direct conduits to groundwater, making a pathway for bacteria to enter your well water.

Wells that are not cased deeply enough could be allowing bacteria to enter your well from geologic features on the landscape, such as sink holes, that are prevalent in the Driftless Region’s karst geology. For this reason, drilling a deeper well may not be the only or best answer – investigating how deeply your well is cased is the first step.

Masarik says that if coliform bacteria were present in your well test, the following steps are recommended:

1. use an alternative source of water for drinking

2. Re-test your well

3. Try to identify any sanitary defects such as a loose or non-existent well cap, well construction faults, a cross-connection, a nearby unused well or pit, and inadequate filtration by soil

4. Disinfect the well

5. Re-test to ensure the well is bacteria-free.

“For recurring bacteria problems, the best solution may be a new well, or if a new well is unlikely to remedy the problem because of the geology where your well is located, then you may need to seek approval for a water treatment system,” Masarik explained.