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Well water testing in Waukesha County, Wisconsin
Waukesha County has more people on household wells than any other Wisconsin county in USGS's estimates, and the county runs a state-certified lab that tests well water and does well evaluations for home sales. Here's what past testing found and what to know if you're buying. Every fact has a source.
How many people here use a private well
USGS estimates that about 132,000 people in Waukesha County supplied their own household water in 2015, about 33% of the county's population, the most of any Wisconsin county.1 The county says there are more than 40,000 private wells in Waukesha County.2
What past testing found
A USGS and UW-Stevens Point groundwater summary for Waukesha County (data as of May 2007) reported:3
| Test | Private well results |
|---|---|
| Nitrate | 97% of 664 samples (1990–2006) met the drinking water standard |
| Arsenic | 90% of 61 samples met the drinking water standard |
| Herbicides | About 21% of wells in a 2002 regional study had a detection |
The same summary counted 427 open contamination sites in the county at the time.3 This is older data; your own test is what counts.
Statewide, the Wisconsin Department of Health Services lists Washington and Jefferson counties, which border Waukesha County, among the areas where arsenic is most common.4
What to test and how often
Wisconsin DNR recommends testing for bacteria and nitrate every year and arsenic every five years.5
Buying a home with a well in Waukesha County
- State rules: Wisconsin doesn't require a well inspection or water test when a home is sold. If an inspection is done, it must be by a licensed well driller or pump installer, on DNR's form, and must include coliform bacteria, nitrate and arsenic, plus a search for unused wells.6
- County service: Waukesha County Environmental Health does well and septic evaluations for property sales and refinancing.2 Call for current fees.
- Unused wells must be properly filled and sealed.6 Waukesha County offers cost-sharing for well abandonment.2
Our Wisconsin page and homebuyer's guide cover contingencies, flow tests and negotiating.
Testing through Waukesha County
- The county's lab is certified by the state. Samples are accepted Monday–Thursday, 8 a.m.–3 p.m.2
- If a first sample is unsafe for bacteria, the county says a second sample is needed to confirm it.2
- Waukesha County Environmental Health: 515 W. Moreland Blvd., Suite AC260, Waukesha. 262-896-8300, [email protected].2
Check the county's page for current prices and kit pickup.
Labs and well records
- Certified labs: DNR's bacteria lab list and certified lab lists.5
- Well records: DNR's well construction report search.7
Where to get tested and treatment options
Related guides
- Buying a home with a well
- Private wells in Wisconsin
- How to read your well water test results
- How often to test a private well
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Dieter, C.A., and others, 2018, Estimated Use of Water in the United States County-Level Data for 2015 (ver. 2.0), U.S. Geological Survey data release. https://doi.org/10.5066/F7TB15V5 ↩
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Waukesha County, "Private Well Water Quality and Laboratory Services." https://www.waukeshacounty.gov/parks-and-land-use/environmental-health/private-well-water-quality-and-laboratory-services/ ↩↩↩↩↩↩
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USGS Wisconsin Water Science Center and UW-Stevens Point, "Protecting Groundwater in Wisconsin through Comprehensive Planning: Waukesha County Executive Summary" (data as of May 2007). https://wi.water.usgs.gov/gwcomp/find/waukesha/index.html ↩↩
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Wisconsin Department of Health Services, "What's in Your Water? A Look at Private Well Water Quality in Wisconsin" (P-01830, July 2017) (PDF). https://www.dhs.wisconsin.gov/publications/p01830.pdf ↩
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Wisconsin DNR, "Test your private well water annually." https://dnr.wisconsin.gov/topic/Wells/privateWellTest.html ↩↩
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Wisconsin DNR, "Buying or selling a home or property with a private well: Property transfer well inspections." https://dnr.wisconsin.gov/topic/Wells/RETransfer.html ↩↩
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Wisconsin DNR, "Well Construction Information System" (public search). https://apps.dnr.wi.gov/wellconstructionpub/#!/PublicSearch/Index ↩