Certified Water Testing Labs in Wisconsin

The Wisconsin Department of Natural Resources, through the Safe Drinking Water Act certified laboratories — chemistry (NR 809/NR 812). The program follows the EPA's national framework for drinking water laboratory certification, which requires EPA-approved test methods, at least annual proficiency testing, and periodic on-site audits. Source: Wisconsin Department of Natural Resources — Laboratory Certification Program (https://dnr.wisconsin.gov/topic/labCert/certified-lab-lists) and EPA (epa.gov/dwlabcert).

52 certified drinking water labs are located in Wisconsin, as of the official list we pulled on August 2, 2026. The Wisconsin Department of Natural Resources also certifies 17 labs based outside Wisconsin that can often still analyze your sample; those appear on the official list linked on this page. Certification changes throughout the year, so treat this as a starting point and confirm status with the lab. Source: Wisconsin Department of Natural Resources — Laboratory Certification Program (https://dnr.wisconsin.gov/topic/labCert/certified-lab-lists).

The EPA recommends testing private wells annually for total coliform bacteria, nitrates, total dissolved solids, and pH — and testing immediately after flooding, well repairs, nearby construction, or any change in your water's taste, odor, or color. Your local health department can tell you which contaminants are common in Wisconsin groundwater. Source: EPA, Protect Your Home's Water (epa.gov/privatewells).

This list covers labs located in Wisconsin that were on the official list published by the Wisconsin Department of Natural Resources as of August 2, 2026. Certification changes during the year, so a lab missing from this page may have been certified since then — the official source linked above always has the current list and it also includes certified labs based outside the state. What we'd avoid is any lab that can't show a current drinking water certification at all. The EPA's guidance is to only use certified laboratories for drinking water testing. Source: EPA, Protect Your Home's Water (epa.gov/privatewells).

Ask the lab about a mail-in collection kit — many certified labs ship one with instructions and pre-treated bottles. Timing matters for some tests (bacteria samples have a short window between collection and analysis), so follow the lab's collection instructions exactly. Your local health department is also worth a call; some offer private well testing for free. Source on health department testing: EPA, Protect Your Home's Water (epa.gov/privatewells).