Well water in Cedar Lake, Wisconsin
In Cedar Lake, <1% of 124 private wells tested between 1990 and 2025 had nitrate above the Wisconsin enforcement standard (10 mg/L), according to the UWSP Well Water Quality Viewer.
124 private wells tested 2020 to 2023 in state summaries; 1 individual samples from 1 wells, 1972. Data refreshed September 9, 2026.
What homeowner tests found
Wisconsin Well Water Quality Viewer samples: private wells tested and reported to the state, 2020 to 2023. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
| Contaminant | Wells tested | Above state level | Median | 95th pct | Highest | State level | |
|---|---|---|---|---|---|---|---|
| Iron | 13 | 46% | 113 | 6,354 | 6,354 | 300 ug/L | |
| Manganese | 13 | 46% | 281 | 1,852 | 1,852 | 300 ug/L | |
| Total coliform | 4 | 25% | |||||
| Nitrate | 124 | <1% | 0.16 | 3.86 | 10.4 | 10 mg/L | |
| Arsenic | 18 | 0% | 0 | 7 | 7 | 10 ug/L | |
| Chloride | 15 | 0% | 4 | 12.6 | 12.6 | 250 mg/L | |
| Copper | 13 | 0% | 0.002 | 0.044 | 0.044 | 1.3 mg/L | |
| Sodium | 13 | 0% | 3.51 | 4.17 | 4.17 | 20 mg/L | |
| Lead | 13 | 0% | 0 | 0 | 0 | 15 ug/L | |
| E. coli | 1 | 0% |
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What this means
Among homeowners in Cedar Lake who sent a sample to the state lab, the health-based limits most often exceeded were nitrate (<1% of 124 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
Iron and manganese exceed the state's advisory level in a sizable share of wells; these are mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Cedar Lake
- Iron46% of 13 local wells tested were above the Wisconsin nuisance level.
- Manganese46% of 13 local wells tested were above the Wisconsin enforcement standard.
- Nitrate<1% of 124 local wells tested were above the Wisconsin enforcement standard.
- Coliform bacteriaRecommended for every private well, every year.
- ChlorideDetected in 100% of local samples.
Contamination sources on record in Cedar Lake
Wisconsin DNR records 3 regulated sites in Cedar Lake, among 3 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 2
- lined landfills and transfer facilities
- 1
- other remediation project
Treatment that fits the local profile
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
- Chloride
- Point-of-use reverse osmosis; Distillation
Get your Cedar Lake water tested at home
A licensed local water treatment company tests your tap water in your home, walks you through the numbers, and quotes treatment only if something needs fixing. Free, about 30 minutes, no obligation. Tell us what you need and we match you with a company that serves Cedar Lake.
Common questions
How often should I test a private well in Cedar Lake?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Sources
- USGS Water Quality Portal: 1 samples in Cedar Lake. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- Wisconsin Well Water Quality Viewer samples: summaries for 10 contaminants in Cedar Lake, up to 124 wells each. Private well samples compiled by the UWSP Center for Watershed Science and Education from the DNR Groundwater Retrieval Network, DATCP surveys, the UWSP Water and Environmental Analysis Lab and county health programs, published in the Wisconsin Well Water Quality Viewer with Wisconsin DHS. Samples are located to the town, village or city they fall in; one result per well and parameter (the latest) so repeat samples do not double count; wells without a state well number are keyed by location. Shares are against Wisconsin NR 140 enforcement standards (arsenic 10 ug/L, nitrate 10 mg/L as N, manganese 300 ug/L, lead 15 ug/L, copper 1.3 mg/L) and the iron and chloride secondary levels. Many samples were submitted by homeowners with a reason to test, so shares can run above a random survey. Retrieved September 9, 2026.
- Wisconsin DNR regulated sites: 3 regulated sites located in Cedar Lake. Open and closed remediation activities (BRRTS, including leaking underground storage tanks and spills) and landfill and waste sites from the Wisconsin Department of Natural Resources. Retrieved September 9, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.