Tap Water Quality Report
Tap water quality in Madison, Wisconsin
Tap water in Madison, Wisconsin receives a grade of D (60/100) from TapWaterSafety.org. It's served by Madison Department of Public Works. The most significant water quality concerns are: Lead detected in source water; Arsenic significantly above health guideline; Chromium-6 detected; Radium-228 detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database, and Madison's published Consumer Confidence Report.
What's in Madison's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Madison.
Lead detected in source water
Severe concernLead detected at 1.1 ppb. EWG considers no level of lead safe; EPA's action level is 15 ppb.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 0.648 ppb, 162x above the EWG health guideline of 0.004 ppb.
Chromium-6 detected
Moderate concernChromium-6 detected at 0.44 ppb.
Radium-228 detected
Moderate concernRadium-228 detected at 0.06 pCi/L.
Recommended filters for Madison
Filters matched to the specific contaminants in Madison's water supply.
NSF/ANSI 53 certified for lead removal
$80-$750NSF 53 is the gold standard certification for lead removal. Required when lead is a documented concern.
Reverse Osmosis
$249-$750Arsenic is most effectively removed by reverse osmosis. Some specialized adsorptive filters also work.
Reverse Osmosis or water softener
$249-$750RO removes radium effectively; ion-exchange water softeners also reduce radium concentration.
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 |
|---|---|---|---|---|---|---|---|---|
| Arsenic Heavy metal |
0.648 ppb | 0.004 | 10 | 10 | 10 | 0.004 | 2023 | 162× over |
| Haloacetic Acids (HAA5) Disinfection byproduct |
5.87 ppb | 0.1 | 60 | 60 | — | — | 2023 | 59× over |
| Chromium-6 (Hexavalent) Heavy metal |
0.44 ppb | 0.02 | — | — | — | 0.02 | 2024 | 22× over |
| Total Trihalomethanes (TTHMs) Disinfection byproduct |
5.2 ppb | 0.6 | 80 | 100 | — | — | 2024 | 8.7× over |
| Nitrate Inorganic |
1.02 mg/L | 0.14 | 10 | 11.3 | 11.3 | 10 | 2022 | 7.3× over |
| Radium-228 Radiological |
0.069 pCi/L | 0.019 | 5 | — | 0.1 | 0.019 | 2023 | 3.6× over |
| Lead Heavy metal |
1.1 ppb | 0 | 15 | 5 | 10 | 0.2 | 2024 | — |
| Contaminant | Detected (2024) | EWG | EPA | EU DWD | WHO | CA PHG | Status |
|---|---|---|---|---|---|---|---|
| Chromium-6 (Hexavalent) Heavy metal |
0.44 ppb | 0.02 | — | — | — | 0.02 | 22× over |
| Total Trihalomethanes (TTHMs) Disinfection byproduct |
5.2 ppb | 0.6 | 80 | 100 | — | — | 8.7× over |
| Lead Heavy metal |
1.1 ppb | 0 | 15 | 5 | 10 | 0.2 | — |
| Contaminant | Detected (2023) | EWG | EPA | EU DWD | WHO | CA PHG | Status |
|---|---|---|---|---|---|---|---|
| Arsenic Heavy metal |
0.648 ppb | 0.004 | 10 | 10 | 10 | 0.004 | 162× over |
| Haloacetic Acids (HAA5) Disinfection byproduct |
5.87 ppb | 0.1 | 60 | 60 | — | — | 59× over |
| Radium-228 Radiological |
0.069 pCi/L | 0.019 | 5 | — | 0.1 | 0.019 | 3.6× over |
| Contaminant | Detected (2022) | EWG | EPA | EU DWD | WHO | CA PHG | Status |
|---|---|---|---|---|---|---|---|
| Nitrate Inorganic |
1.02 mg/L | 0.14 | 10 | 11.3 | 11.3 | 10 | 7.3× over |
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 Department of Public Works.
General Contact
Water Quality Contact
For questions about contaminants or test results.