# Madison, WI — Drinking Water Quality (2024)

> Contaminant levels for the Madison, WI public water system from its 2024 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/wi/madison/2024
- JSON API: https://www.thewatermap.com/api/water/wi/madison/2024
- Source: the utility's annual Consumer Confidence Report (CCR)
- Verification: transcribed by a model, cross-checked by a second model, approved before publishing
- Reporting year: 2024
- Contaminants measured: 27
- Contaminants with a federal limit: 23
- Contaminants at or above the federal limit: 1
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| HAA5 | Disinfection byproducts | 1.5 ug/L (Average) | Median Level Found | 60 ug/L (MCLG) | Within the limit |
| TTHM | Disinfection byproducts | 5.5 ug/L (Average) | Median Level Found | 80 ug/L (MCL) | Within the limit |
| Chloride | Inorganic chemicals | 16 mg/L (Average) | Median Level Found | 250 mg/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.7 mg/L (Average) | Median Level Found | 4 mg/L (MCLG) | Within the limit |
| Nitrate | Inorganic chemicals | 0.9 mg/L (Average) | Median Level Found | 10 mg/L (MCLG) | Within the limit |
| Sulfate | Inorganic chemicals | 18 mg/L (Average) | Median Level Found | 250 mg/L (MCL) | Within the limit |
| Barium | Metals | 21 ug/L (Average) | Median Level Found | 2 ug/L (MCLG) | At or above the limit |
| Chromium, Hexavalent | Metals | 0.4 ug/L (Average) | Median Level Found | No federal limit | Detected — no federal limit |
| Chromium, Total | Metals | Not detected ug/L (Average) | Median Level Found | 100 ug/L (MCLG) | Within the limit |
| Copper | Metals | 150 ug/L (90th percentile) | At the tap | 1300 ug/L (MCLG) | Within the limit |
| Iron | Metals | Not detected mg/L (Average) | Median Level Found | 0.3 mg/L (MCL) | Within the limit |
| Lead | Metals | 1.8 ug/L (90th percentile) | At the tap | 15 ug/L (Action level) | Within the limit |
| Manganese | Metals | 2.5 ug/L (Average) | Median Level Found | 50 ug/L (MCL) | Within the limit |
| Nickel | Metals | Not detected ug/L (Average) | Median Level Found | 100 ug/L (MCL) | Within the limit |
| Selenium | Metals | Not detected ug/L (Average) | Median Level Found | 50 ug/L (MCLG) | Within the limit |
| Sodium | Metals | 7.3 mg/L (Average) | Median Level Found | No federal limit | Detected — no federal limit |
| Strontium | Metals | 82 ug/L (Average) | Median Level Found | No federal limit | Detected — no federal limit |
| Zinc | Metals | 3.8 ug/L (Average) | Median Level Found | 5 ug/L (MCL) | Within the limit |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | 6.6–7.3 (Range) | System-wide | 10 (MCL) | Within the limit |
| PFBA | PFAS ("forever chemicals") | 36–47 (Range) | System-wide | No federal limit | Detected — no federal limit |
| PFOA | PFAS ("forever chemicals") | Not detected ng/L (Average) | Median Level Found | 4 ng/L (MCL) | Within the limit |
| PFOS | PFAS ("forever chemicals") | Not detected ng/L (Average) | Median Level Found | 4 ng/L (MCL) | Within the limit |
| Combined Radium | Radionuclides | 2.4 pCi/L (Average) | Median Level Found | 5 pCi/L (MCL) | Within the limit |
| Gross Alpha | Radionuclides | 1.3 pCi/L (Average) | Median Level Found | 15 pCi/L (MCL) | Within the limit |
| Atrazine | VOCs & pesticides | Not detected ug/L (Average) | Median Level Found | 3 ug/L (MCLG) | Within the limit |
| Tetrachloroethylene | VOCs & pesticides | Not detected ug/L (Average) | Median Level Found | 5 ug/L (MCL) | Within the limit |
| Trichloroethylene | VOCs & pesticides | Not detected ug/L (Average) | Median Level Found | 5 ug/L (MCL) | Within the limit |

## What these contaminants are

- **HAA5** — Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. Long-term exposure above the federal limit is associated with an increased cancer risk.
- **TTHM** — Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.
- **Chloride** — A naturally occurring salt compound. Regulated only as a secondary (cosmetic) standard; high levels cause a salty taste and can corrode pipes.
- **Fluoride** — A mineral often added to drinking water to help prevent tooth decay. Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.
- **Nitrate** — A compound from fertilizer runoff, septic systems, and erosion of natural deposits. Levels above the federal limit can cause 'blue baby syndrome,' a serious oxygen-transport condition in infants.
- **Sulfate** — A naturally occurring mineral from rock and soil. No health-based federal limit; high levels can have a laxative effect and a bitter taste.
- **Barium** — A metal from erosion of natural deposits and industrial discharge. Long-term exposure above the federal limit can raise blood pressure.
- **Chromium, Hexavalent** — Hexavalent chromium ('chromium-6') — the more toxic form of chromium. A known carcinogen by inhalation; regulated nationally only within the total-chromium limit, with stricter limits in some states.
- **Chromium, Total** — Total chromium — the sum of all chromium forms, from natural deposits and industrial discharge. Long-term exposure above the federal limit can cause allergic dermatitis; includes hexavalent chromium.
- **Copper** — A metal that enters water from corroding household plumbing. Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.
- **Iron** — A naturally occurring metal common in groundwater. Regulated only as a secondary (cosmetic) standard; causes rusty color, staining, and metallic taste.
- **Lead** — A toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. There is no safe level of lead; it harms brain development in children and raises blood pressure in adults. The EPA sets an action level, not a health goal above zero.
- **Manganese** — A naturally occurring metal from soil and rock. No enforceable federal limit; high levels stain fixtures and laundry and can affect taste, with a health advisory for infants.
- **Nickel** — A metal from natural deposits and industrial discharge. Long-term exposure can cause skin and other effects; monitored under EPA rules.
- **Selenium** — A trace element from natural deposits and industrial discharge. Essential in tiny amounts, but long-term exposure above the federal limit can cause hair and fingernail loss and circulatory problems.
- **Sodium** — A naturally occurring salt component. Not federally regulated for health; relevant for people on sodium-restricted diets.
- **Zinc** — A naturally occurring metal that can also enter water from corroding pipes. Regulated only as a secondary (cosmetic) standard; high levels cause a metallic taste.
- **Perfluorohexanesulfonic acid** — Perfluorohexanesulfonic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **PFBA** — Perfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment and the human body.
- **PFOA** — Perfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
- **PFOS** — Perfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
- **Combined Radium** — Combined radium-226 and radium-228 — naturally occurring radioactive elements. Long-term exposure above the federal limit increases the risk of bone cancer.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
- **Atrazine** — A widely used agricultural herbicide that reaches water through runoff. Long-term exposure above the federal limit can affect the cardiovascular and reproductive systems.
- **Tetrachloroethylene** — An industrial solvent (PCE) used in dry cleaning and degreasing. A likely human carcinogen; long-term exposure above the federal limit can damage the liver and kidneys.
- **Trichloroethylene** — An industrial solvent (TCE) used in metal degreasing. A known human carcinogen; long-term exposure above the federal limit can damage the liver.

## How to read this

- A water-quality report covers an entire service area, not a single address.
- 'Federal limit' is the EPA standard (MCL, action level, treatment technique, etc.) that the measured level is compared against.
- 'At or above the federal limit' means the utility's own reported figure met or exceeded that standard.

_Figures are the utility's own published numbers. Generated 2026-05-25 from thewatermap.com._