Water quality
Wisconsin water quality
According to the Wisconsin Department of Natural Resources (DNR), nitrate is the state's most widespread groundwater contaminant, with the DNR reporting that at least 10% of private wells and about 300 public systems exceed the nitrate health standard. The DNR has also documented severe PFAS contamination of private wells in the Marinette and Peshtigo area linked to firefighting foam. Wisconsin has more than 176,000 lead service lines still needing replacement, and water is generally hard across much of the state.
Documented considerations
Nitrates
According to the Wisconsin DNR, nitrate is the state's most widespread groundwater contaminant; at least 10% of private wells and roughly 300 public water systems have nitrate exceeding the health standard.
PFAS
According to the Wisconsin DNR, firefighting foam from Tyco Fire Products' Marinette training facility contaminated private wells in the Marinette and Peshtigo area, with some PFOA/PFOS detections far exceeding state limits; affected residents receive bottled water.
Lead
According to the Wisconsin DNR, more than 176,000 lead service lines across the state need replacing, and the agency has allocated tens of millions of dollars to help communities remove them.
Hardness
According to USGS hardness mapping, much of Wisconsin sits over mineral-dense aquifers, producing hard to very hard water in many communities.
Certified filters for Wisconsin's main concerns
- 7.2AquaTru Classic Countertop RO
A no-plumbing countertop 4-stage RO purifier certified to NSF standards for lead, PFAS, fluoride and arsenic with an efficient drain ratio.
- 7.5Culligan US-EZ-4 Under-Sink
An under-sink filter genuinely IAPMO certified to NSF/ANSI 42, 53 and 401 for lead, cysts, VOCs, mercury and PFOA/PFOS.
- 7.2Aquasana AQ-5200 Under-Sink
Certified for lead and PFAS, cheap per gallon, marketing matches the certified scope.
- 4.9ZeroWater 5-Stage Pitcher (7-Cup)
A five-stage ion-exchange pitcher certified for lead, chromium-6 and PFOA/PFOS - but a short 15-gallon filter makes it costly to run.
- 7.3Brita Elite Pitcher (10-Cup)
A pour-through pitcher whose Elite filter is certified to reduce lead, mercury, cadmium and more, with a long 120-gallon cartridge.
- 6.8Frizzlife SK99 Under-Sink Filter
A direct-connect 3-stage under-sink filter with a 0.5 micron carbon block, IAPMO certified to NSF/ANSI 42 and 53 for chlorine, lead and chloramine.
FAQ
- Is Wisconsin tap water safe to drink?
- According to the Wisconsin DNR, most public systems meet federal standards, but nitrate is widespread in groundwater and private wells, and PFAS has heavily affected wells near Marinette. Well owners are advised to test regularly.
- How bad is nitrate in Wisconsin water?
- According to the Wisconsin DNR, nitrate is the state's most common groundwater contaminant, exceeding the health standard in at least 10% of private wells and about 300 public water systems, largely from agricultural sources.
- Does Wisconsin have lead pipes?
- Yes. According to the Wisconsin DNR, over 176,000 lead service lines remain across the state, and funding has been provided to help communities replace them. Lead enters water through these lines and older home plumbing.
Sources
- Wisconsin DNR - PFAS Contamination in Marinette and Peshtigo
- Wisconsin DNR - Clean Drinking Water
- USGS - Map of Water Hardness in the United States
Not sure how to read your local report? See our guide on reading a water quality report.