Tap Water Quality Report
Tap water quality in Madison, Wisconsin
Tap water in Madison, Wisconsin receives a grade of F (59/100) from TapWaterSafety.org. It's served by MADISON WATER UTILITY. The most significant water quality concerns are: PFAS contamination; Perfluorohexane sulfonate (PFHXS) significantly above health guideline; Radon significantly above health guideline; Total PFOS and PFOA significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in Madison's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Madison.
PFAS contamination
Severe concernPerfluorooctanoic acid (PFOA), Total PFOS and PFOA detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Perfluorohexane sulfonate (PFHXS) significantly above health guideline
Moderate concernPerfluorohexane sulfonate (PFHXS) detected at 2.25 ppt, 2246x above the EWG health guideline of 0.001 ppt.
Radon significantly above health guideline
Moderate concernRadon detected at 223.0 pCi/L, 149x above the EWG health guideline of 1.5 pCi/L.
Total PFOS and PFOA significantly above health guideline
Moderate concernTotal PFOS and PFOA detected at 0.523 ppt, 75x above the EWG health guideline of 0.007 ppt.
EPA compliance record
Official U.S. EPA records for MADISON WATER UTILITY (system ID WI1130224) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Public Notice Rule and Revised PN Rule | Other (e.g. public notice) | 10/17/2024 | Open |
| Lead and Copper Rule Revisions | Required treatment not met | 10/17/2024 | Resolved |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for Madison
Filters matched to the specific contaminants in Madison's water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in Madison's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Perfluorohexane sulfonate (PFHXS) PFAS |
2.25 ppt | 0.001 | 10.0 | — | — | — | — | 2246× over |
| Radon Radiological |
223.0 pCi/L | 1.5 | — | — | — | — | — | 149× over |
| Total PFOS and PFOA PFAS |
0.523 ppt | 0.007 | — | 100 | 100 | 0.007 | — | 75× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
2.35 ppb | 0.06 | — | — | — | — | — | 39× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
5.2 ppb | 0.15 | 80.0 | 100 | — | — | — | 35× over |
| Chromium (hexavalent) Heavy metal |
0.657 ppb | 0.02 | — | — | — | — | — | 33× over |
| Radium, combined (-226 and -228) Radiological |
1.46 pCi/L | 0.05 | 5.0 | — | — | — | — | 29× over |
| Tetrachloroethylene (perchloroethylene) Volatile organic compound |
1.01 ppb | 0.06 | 5.0 | — | — | — | — | 17× over |
| Dibromoacetic acid Disinfection byproduct |
0.47 ppb | 0.03 | — | — | — | — | — | 16× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
1.19 ppb | 0.1 | 60.0 | 60 | — | — | — | 12× over |
| Bromodichloromethane Disinfection byproduct |
0.634 ppb | 0.06 | — | — | — | — | — | 11× over |
| Nitrate Inorganic |
1.27 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 9.0× over |
| Nitrate and nitrite Inorganic |
1.25 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 8.9× over |
| Dibromochloromethane Disinfection byproduct |
0.64 ppb | 0.1 | — | — | — | — | — | 6.4× over |
| Perfluoroheptane sulfonic acid (PFHpS) PFAS |
0.005 ppt | 0.001 | — | — | — | — | — | 5.0× over |
| Perfluorooctanoic acid (PFOA) PFAS |
0.426 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 4.7× over |
| Chloroform Disinfection byproduct |
1.21 ppb | 0.4 | — | — | — | — | — | 3.0× over |
| Dichloroacetic acid Disinfection byproduct |
0.523 ppb | 0.2 | — | — | — | — | — | 2.6× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.424 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 1.4× over |
| Trichloroacetic acid Disinfection byproduct |
0.124 ppb | 0.1 | — | — | — | — | — | 1.2× over |
| Uranium Radiological |
0.32 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | Below guideline |
| Bromoform Disinfection byproduct |
0.226 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Perfluoropentane sulfonic acid (PFPeS) PFAS |
0.17 ppt | 1.0 | — | — | — | — | — | Below guideline |
| Trichloroethylene Volatile organic compound |
0.0531 ppb | 0.4 | 5.0 | 10 | 20 | 1.7 | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.0434 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| 6:2 Fluorotelomer Sulfonic Acid (6:2 FTSA) Other |
0.124 ppt | 1.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
8.05 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Atrazine Pesticide/Herbicide |
0.00684 ppb | 0.1 | 3.0 | 0.1 | 100 | 0.15 | — | Below guideline |
| Barium Heavy metal |
25.0 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Strontium Radiological |
22.1 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
1.71 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Selenium Heavy metal |
0.222 ppb | 30.0 | 50.0 | 20 | 40 | 30 | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
3.92 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.0733 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.0552 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Chloromethane Other |
0.00316 ppb | 2.69 | — | — | — | — | — | Below guideline |
| Cobalt Other |
0.0517 ppb | 70.0 | — | — | — | — | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
0.467 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
0.464 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| 1,1-Dichloroethane Volatile organic compound |
0.000614 ppb | 3.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.364 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
0.131 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Trichlorofluoromethane Other |
0.128 ppb | 1300.0 | — | — | — | — | — | Below guideline |
| Aluminum Heavy metal |
0.0528 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Trichlorotrifluoroethane Other |
0.00857 ppb | 4000.0 | — | — | — | — | — | Below guideline |
| Xylenes (total) Volatile organic compound |
0.00375 ppb | 1800.0 | 10000.0 | — | — | — | — | Below guideline |
| 1,1-Dichloroethylene Volatile organic compound |
0.00352 ppb | — | 7.0 | — | — | — | — | Below guideline |
| 1-Butanol Other |
0.183 ppb | — | — | — | — | — | — | Below guideline |
| 2-Methoxyethanol Other |
0.0122 ppb | — | — | — | — | — | — | Below guideline |
| Chromium (total) Heavy metal |
0.292 ppb | — | 100.0 | — | — | — | — | Below guideline |
| cis-1,2-Dichloroethylene Volatile organic compound |
0.0423 ppb | — | 70.0 | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.732 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Metolachlor Pesticide/Herbicide |
0.000522 ppb | — | — | — | — | — | — | Below guideline |
| Nitrite Inorganic |
0.00467 ppm | — | 1.0 | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from MADISON WATER UTILITY.