Certified labs by state
Wisconsin
Wisconsin says about 30% of residents get drinking water from private wells, and state guidance for homeowners is split mainly between DHS health advice and DNR well, lab, and grant resources. Wisconsin also calls out several region-specific issues for private wells, including arsenic in northeastern areas, strontium in eastern and northern areas, and elevated radon and uranium mainly in north-central parts of the state. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
Checked against official sources on October 4, 2026. Rules and links change; confirm with the office listed before you act.
- Certifies drinking water labs
- Wisconsin Department of Natural Resources
- Official certified lab list
- Official page →
- Free or low-cost testing
- Wisconsin DHS says WellTAP may provide no-cost testing through local or Tribal health departments for qualifying primary-residence well users facing a financial or other burden; qualifying households must include someone pregnant, a child 12 or under, or a person with a weakened immune system. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
Official resources in Wisconsin
Main homeowner page for what to test, how often to test, and contaminant-specific guidance including WellTAP eligibility. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
Official DNR page with Wisconsin drinking-water certified lab lists for homeowners and other laboratory certification resources. ([dnr.wisconsin.gov](https://dnr.wisconsin.gov/topic/labCert/certified-lab-lists))
Official DNR homeowner hub for private well construction, maintenance, county specialists, and links to well compensation and abandonment funding. ([dnr.wisconsin.gov](https://dnr.wisconsin.gov/topic/Wells/homeowners.html))
Official grant page for eligible owners or renters seeking reimbursement for contamination-related testing, treatment, replacement, reconstruction, or temporary water. ([dnr.wisconsin.gov](https://dnr.wisconsin.gov/aid/WellCompensation.html))
Official DHS guidance on when private well users may want to test well water for radon and how Wisconsin interprets radon-in-water risk. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/radon/radon-water.htm))
Key facts for Wisconsin
- Wisconsin DHS recommends private well users test bacteria and nitrate at least annually, and arsenic and lead at least every five years. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
- DHS says test strontium if you live in eastern or northern Wisconsin, twice over two years in different seasons, ideally fall and spring. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
- DHS says test for TCE if you live within a quarter mile of a landfill, industrial site, gas station, or dry cleaner. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
- WSLH says only north-central Wisconsin is known to have significantly elevated radon in well water; DHS recommends action for private wells at 10,000 pCi/L or greater. ([slh.wisc.edu](https://www.slh.wisc.edu/environmental/radiochemistry/radiochemical-analyses/))
- WSLH says some private wells in north-central Wisconsin have total uranium levels over 350 pCi/L, and homeowners should contact the lab, DNR, or DHS before ordering uranium tests. ([slh.wisc.edu](https://www.slh.wisc.edu/environmental/radiochemistry/radiochemical-analyses/))
- DNR’s Well Compensation Grant can reimburse eligible contamination-related water tests and other corrective costs, but bacteria and nitrate are generally excluded except limited cases listed by DNR. ([dnr.wisconsin.gov](https://dnr.wisconsin.gov/aid/WellCompensation.html))
What to do next
- Start with the DHS private wells page, then use DNR’s certified-lab page to choose a Wisconsin-certified lab for the specific analytes you need. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
- If your household includes a pregnant person, child 12 or under, or someone immunocompromised, ask your local or Tribal health department about WellTAP no-cost testing. ([dhs.wisconsin.gov](https://www.dhs.wisconsin.gov/water/private.htm))
- If results suggest contamination, contact a DNR private water supply specialist and review whether the Well Compensation Grant could help with follow-up testing or corrective work. ([dnr.wisconsin.gov](https://dnr.wisconsin.gov/topic/Wells/homeowners.html))
Helpful guides
- How to choose a state-certified drinking water lab
- What to test your private well water for (and how often)
- How to collect a well water sample without ruining the test
- How to read a water test report: MCLs, units and flags