Drinking water quality · 2024
· Verified
What's in Madison, WI tap water
30 contaminants were measured in the Madison, WI water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 30
- Over federal limit
- 0
- Approaching the limit
- 0
- Service area
- WI
Where your water comes from · EPA SDWIS
Madison, WI's drinking water comes from ground water, drawn from 2 sources.
Source
- YP894
- YP889
Treatment
- YP894
- YP889
Distribution
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Treatment technique violationHealth-based1 violation on record · most recent Jan 2012resolved
- Other1 violation on record · most recent Jan 20121 open
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.' | 6.6–7.3 ng/LRangeSystem-wide | 10 ng/LMCL | Within the limit |
| PFOAPerfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. | Not detected ng/LAverageMedian Level Found | 4 ng/LMCL | Within the limit |
| PFOSPerfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. | Not detected ng/LAverageMedian Level Found | 4 ng/LMCL | Within the limit |
| PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' | 36–47 ng/LRangeSystem-wide | None set | Detected — no federal limit |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Radium 226 228 | 2.4 pCi/LAverageMedian Level Found | 5 pCi/LMCL | Within the limit |
| Cis Dichloroethylene 12 | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
| Dichloroethylene 11 | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
| Pce | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
| Tce | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
| Dichloroethane 12 | Not detectedAverageMedian Level Found | None set | Detected — no federal limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 0.0032 mg/L90th percentileAt the tap | 0.015 mg/LAction level | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 150 ug/L90th percentileAt the tap | None set | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 21 ug/LAverageMedian Level Found | 2 ug/LMCLG | Within the limit |
| Chromium, TotalTotal chromium — the sum of all chromium forms, from natural deposits and industrial discharge. | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
| SeleniumA trace element from natural deposits and industrial discharge. | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 0.4 ug/LAverageMedian Level Found | None set | Detected — no federal limit |
| IronA naturally occurring metal common in groundwater. | Not detected mg/LAverageMedian Level Found | None set | Detected — no federal limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
| ManganeseA naturally occurring metal from soil and rock. | 2.5 ug/LAverageMedian Level Found | None set | Detected — no federal limit |
| NickelA metal from natural deposits and industrial discharge. | Not detected ug/LAverageMedian Level Found | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 7.3 mg/LAverageMedian Level Found | None set | Detected — no federal limit |
| Strontium | 82 ug/LAverageMedian Level Found | None set | Detected — no federal limit |
| ZincA naturally occurring metal that can also enter water from corroding pipes. | 3.8 ug/LAverageMedian Level Found | None set | Detected — no federal limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.7 mg/LAverageMedian Level Found | 4 mg/LMCLG | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 0.9 mg/LAverageMedian Level Found | 10 mg/LMCLG | Within the limit |
| ChlorideA naturally occurring salt compound. | 16 mg/LAverageMedian Level Found | None set | Detected — no federal limit |
| SulfateA naturally occurring mineral from rock and soil. | 18 mg/LAverageMedian Level Found | None set | Detected — no federal limit |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | 1.3 pCi/LAverageMedian Level Found | 15 pCi/LMCL | Within the limit |
+By source (2)— Wells with Detections, Median Level Found
| |||
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 5.5 ug/LAverageMedian Level Found | None set | Within the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 1.5 ug/LAverageMedian Level Found | None set | Within the limit |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AtrazineA widely used agricultural herbicide that reaches water through runoff. | Not detected ug/LAverageMedian Level Found | None set | Within the limit |
People also ask about Madison, WI's water
+Is Madison, WI tap water safe to drink in 2024?
Every one of the 30 contaminants measured in Madison, WI's 2024 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in Madison, WI tap water?
30 contaminants were measured in Madison, WI's 2024 Consumer Confidence Report, spanning metals, other, and inorganic chemicals. 9 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Where does the data on this page come from?
Every value is transcribed from Madison, WI's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Madison, WI's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.