Is Milwaukee Tap Water Safe to Drink?
Milwaukee's tap water met every federal limit in its 2025 report. The highest routine reading was Chlorine, Total at 40% of its limit — 1.61 ppm against a 4 ppm maximum residual disinfectant level.
The number that deserves the most attention sits in the lead data. Of the samples taken in 2023, one measured 20.3 ppb against a 15 ppb action level — 1 times the limit — while the 90th percentile across all samples was 5.3 ppb. A citywide statistic and a single tap can be very different numbers, and lead is a property-level problem.
Key figures — 2025 report
- Sites above the lead action level
- 2
- Highest routine reading: Chlorine, Total
- 1.61 ppm against a 4 ppm maximum residual disinfectant level (40%)
- Contaminants tested
- 13 — none above a federal maximum
Serving 923,000 people, PWSID WI2410100.
Lead pathway
Where lead enters Milwaukee's water
Lead is measured where it matters: at customers' taps. Milwaukee's most recent lead and copper compliance round was in 2023. The 90th percentile was 5.3 ppb against a 15 ppb federal action level, and two samples exceeded that level. All samples were collected at customers' taps from properties with lead service lines.
That sampling pool changes what the number means. 5.3 ppb describes the highest-risk properties — homes known to have a lead service line — not a citywide cross-section. The same percentile drawn from a mixed pool of homes would be a worse sign, and comparing it against another city's percentile is invalid unless that city sampled the same way.
The percentile is not the whole story. The worst single sample in that round measured 20.3 ppb — above the 15 ppb action level. A 90th percentile describes the distribution across the sampling pool; it says nothing about the one house with a lead service line or leaded solder. If that house is yours, the outlier is your number, not the percentile. The two households that tested above 15 ppb were contacted immediately for follow-up.
Lead with and without a lead service line
Milwaukee publishes lead for two groups of homes — both measured at the tap, differing in whether the property has a lead service line. That is the clearest published evidence of where the lead comes from:
| Population | Typical result | Worst single sample | Source |
|---|---|---|---|
| Homes WITHOUT a lead service line | median 0.1 µg/L | 3.31 µg/L | 2025 Distribution System Water Quality supplement, routine sampling sites |
| Homes WITH a lead service line | 90th percentile 5.3 ppb | 20.3 ppb (2 sites above the action level) | 2023 Lead and Copper Rule compliance sampling, reported in the CCR |
Homes WITHOUT a lead service line: These lead results are from routine sampling sites that do NOT have a lead service line. Reporting limit 0.5 µg/L.
The two datasets come from different years (2025 distribution monitoring vs 2023 compliance sampling) and different sampling protocols. Present them side by side as what they are — do not compute a difference, a ratio, or a percentage increase from them.
Because lead levels may vary over time, lead exposure is possible even when tap sampling results do not detect lead at one point in time.
Note the dates: this lead data is from 2023, while the report covers 2025.
The utility's own report attributes lead at the tap to service lines and household plumbing — corrosion of the pipes between the main under the street and the faucet — not to Lake Michigan or the treatment plants.
What the utility does about it: corrosion control
The utility adds food-grade orthophosphate to the finished water; at customer taps it averaged 1.74 mg/L (range 1.2 – 6.2), with distribution-system sampling putting the median at 1.76 mg/L. pH in the distribution system ranged from 7.46 to 8.1 (median 7.67).
| Year | What happened |
|---|---|
| 1996 | MWW began adding food-grade orthophosphate to finished water to reduce lead and copper leaching from pipes. |
| 1997 | Treatment fully implemented by year end. Lead concentrations dropped below the EPA action level during the next Lead and Copper Rule compliance cycle. |
| 2022 | After a three-year study to optimise the corrosion control treatment programme, the Wisconsin DNR determined that MWW's water quality characteristics remain ideal for reducing lead in water. No changes were requested. |
Is my service line lead?
How to find out whether your service line is lead
MWW was required to develop an initial inventory of service lines connected to the distribution system by 16 October 2024 and to make it publicly accessible.
Milwaukee maintains a service line inventory at milwaukee.gov/CheckAddress.
If you are concerned about lead in your water, you may wish to have your water tested. The report does not state whether the utility provides testing free of charge.
What the utility recommends at home
- Identify and remove. Identify and remove lead materials in your home plumbing.
- Filter. Filter drinking water using a filter certified to NSF/ANSI 53 standards and follow the filter instructions. Filtered water is recommended for children under 6 and those who are pregnant or breastfeeding.
- Flush. If your water has been unused for 6 or more hours, flush the tap for 3 minutes before using water for drinking, cooking, or making baby formula.
- Consume cold. Use only cold water for drinking, cooking, and making baby formula. Boiling water does NOT remove lead.
- Clean aerators. Remove and clean faucet screens (aerators) regularly.
Full contaminant results
Every detected contaminant in Milwaukee's 2025 report
Thirteen contaminants appear in the detected-results tables. Ten were detected at one or more treatment plants; none exceeded a federal maximum contaminant level.
Not everything in this report is 2025 data: lead and copper are from 2023, and some rows below were sampled in 2023. Each carries its own date where it differs from the report year.
System-wide results
| Contaminant | Your water | Limit | % of limit | Range |
|---|---|---|---|---|
| Chlorine, Total | 1.61 ppm (average) | 4 ppm | 40% | 0.98 – 1.94 |
| Bromate | 2.2 ppb (average) | 10 ppb (running annual average) | 22% | 0 – 4.2 |
| Trihalomethanes, Total | 8.6 ppb (average) | 80 ppb | 11% | 3.4 – 13 |
| Total Haloacetic Acids 5 | 2 ppb (average) | 60 ppb | 3% | 0.7 – 4.8 |
| Fluoride | 0.64 ppm (average) | 4 ppm | 16% | 0.54 – 0.7 |
| Nitrate | 0.3 ppm (average) | 10 ppm | 3% | 0.23 – 0.3 |
| Barium | 0.02 ppm (average) | 2 ppm | 1% | 0.02 – 0.02 |
| Antimony | 0.17 ppb (average) | 6 ppb | 3% | 0.16 – 0.18 |
| Atrazine | 0.02 ppb (average) | 3 ppb | 1% | 0.02 – 0.02 |
| Chromium, Total | 0.8 ppb (average) | 100 ppb | 1% | 0.69 – 0.9 |
| Chlorite | 0 ppm (average) | 1 ppm | — | 0 – 9.29 |
Bromate — distribution supplement: median 2.39 µg/L, maximum 34.3 µg/L. Individual distribution samples reached 34.3 µg/L. Compliance is determined on a running annual average, not on single samples.
Antimony: sampled 7 August 2023 — older than the 2025 report year.
Atrazine: sampled 21 August 2023 — older than the 2025 report year.
Chromium, Total: sampled 9 August 2023 — older than the 2025 report year.
Chlorite: The CCR lists chlorite in ppm with an average of 0.00 and a range up to 9.29, against a 1 ppm MCL, yet marks the row as meeting the standard. The distribution supplement lists chlorite with a regulatory limit of 1000 µg/L and a maximum of 12.1 µg/L (0.0121 ppm). The 9.29 figure is almost certainly µg/L printed under a ppm heading. Both figures are reproduced as printed; no percent-of-limit is computed for this row.
Microbial monitoring
| Measure | Result | Standard |
|---|---|---|
| Total Coliform Bacteria | Maximum 0.06% positive | 5 % positive |
| Heterotrophic Plate Count | Met Standard | Treatment technique |
Total Coliform Bacteria: Two distribution sites tested positive for coliform bacteria, but all re-tests were negative.
Heterotrophic Plate Count — distribution supplement: maximum 798 colonies/mL. Maximum in distribution supplement sampling.
Secondary (aesthetic) parameters
These are measured against secondary standards — federal guidelines for taste, odor and staining, not health-based limits.
| Parameter | Average | Range | Guideline (SMCL) |
|---|---|---|---|
| Aluminium | 0.07 ppm | 0.03 – 0.14 | 0.05 – 0.2 ppm |
| Chloride | 17 ppm | 15 – 26 | 250 ppm |
| Manganese | 0.17 ppb | 0.05 – 0.63 | 50 ppb |
| Sodium | 9.8 ppm | 9.6 – 9.8 | 250 ppm |
| Sulfate | 27 ppm | 25 – 32 | 250 ppm |
| Total Dissolved Solids | 173 ppm | 167 – 179 | 500 ppm |
| Zinc | 0.019 ppm | 0 – 0.028 | 5 ppm |
PFAS and other unregulated contaminants
Milwaukee sampled for unregulated contaminants on 20 February 2023 — note the date: these are not 2025 results. Three compounds were detected:
| Compound | Average | Range | State health guideline | State MCL | Federal MCL (future) |
|---|---|---|---|---|---|
| PFOS (Perfluorooctanesulfonic acid) | 2.2 ppt | 2.1 – 2.2 ppt | 20 ppt | 70 ppt | 4 ppt |
| PFOA (Perfluorooctanoic acid) | 2.2 ppt | 2.1 – 2.2 ppt | 20 ppt | 70 ppt | 4 ppt |
| PFOS + PFOA combined | 4.4 ppt | 4.2 – 4.6 ppt | 20 ppt | 70 ppt | None |
The state columns come from the Wisconsin Department of Health Services: the Recommended Public Health Groundwater Standard (Cycle 11) of 20 ppt and the state MCL of 70 ppt (The Wisconsin regulation applying in 2025). There are no violations for detections of contaminants that exceed the RPHGS or HAL.
The recommended health-based levels shown were in effect in 2025. WDHS revised these levels during 2025; current values are published at dhs.wisconsin.gov/water/gws.htm. Current values: dhs.wisconsin.gov/water/gws.htm.
The utility's own characterisation of the federal picture: "New PFAS regulations were announced in 2024 and are not enforceable yet. The announced federal figure for PFOS and PFOA is 4 ppt. HI (hazard index) refers to a regulation of a mixture of compounds."
Where that leaves Milwaukee: PFOS and PFOA each averaged 2.2 ppt — below the 4.0 ppt federal Maximum Contaminant Levels the EPA finalized in April 2024, which are final but not yet enforceable (systems must comply by 26 April 2029; a proposed exemption pathway to 2031 was not finalized as of August 2026), and far below Wisconsin's 70 ppt state standard and 20 ppt recommended health guideline. These results do not violate any current federal or state drinking water standard, and they also sit below the future federal limits.
Regulatory status verified against EPA sources on 29 August 2026.
Distribution-supplement PFAS sampling: PFOS median 1.9 ng/L (max 2.2) and PFOA median 2.1 ng/L (max 2.1), against a 2 ng/L reporting limit.
Drinking water is one route of PFAS exposure. In Wisconsin, two-thirds of people use groundwater as their drinking water source, and PFAS can reach groundwater from sites that make or use PFAS and from consumer products in landfills. Milwaukee's source is Lake Michigan surface water.
PFAS
Under the EPA's fifth Unregulated Contaminant Monitoring Rule, Milwaukee tested for 29 per- and polyfluoroalkyl substances (PFAS) and 1 lithium in 2023. All results were below the EPA reporting limits. If a contaminant was present, it was at too low a concentration to reliably measure by EPA's standards. That is not a contradiction of the PFAS results on this page: UCMR-5 uses EPA reporting limits, which are higher than the detection limits in the utility's own PFAS monitoring. Both statements are true at their own reporting limits.
24 more substances, reported voluntarily
As the largest water utility in Wisconsin, MWW goes above and beyond the required testing and provides the additional results to customers.
See all 24 voluntarily reported substances
| Substance | Average | Range | Typical source |
|---|---|---|---|
| Chlorate | 105 ppb | 45 – 157 ppb | Byproduct of drinking water disinfection |
| Strontium | 113 ppb | 112 – 114 ppb | Naturally occurring |
| Calcium | 34 ppm | — | Naturally occurring |
| Bromide | 20 ppb | 9.1 – 25 ppb | Naturally occurring |
| Magnesium | 12 ppm | — | Naturally occurring |
| Erucylamide | 3.8 ppb | 0 – 6.4 ppb | Plastic packaging |
| Silica, Total | 2.2 ppm | 2 – 2.3 ppm | Naturally occurring |
| Lithium | 2.1 ppb | 2 – 2.2 ppb | Naturally occurring, batteries, pharmaceuticals |
| o-Phosphate as PO4 | 1.74 ppm | 1.2 – 6.2 ppm | Corrosion control treatment added to coat pipes and prevent lead leaching |
| Total Solids | 191 ppm | 187 – 195 ppm | — |
| Total Organic Carbon | 1.44 ppm | 1.34 – 1.56 ppm | Naturally occurring |
| Potassium | 1.5 ppm | — | Naturally occurring |
| Rubidium | 1.1 ppb | — | Naturally occurring |
| Molybdenum | 0.98 ppb | 0.84 – 1.2 ppb | Naturally occurring and industrial processes |
| Bromochloroacetic acid | 0.99 ppb | 0 – 1.5 ppb | Byproduct of drinking water disinfection |
| Bromodichloroacetic acid | 0.99 ppb | 0 – 1.7 ppb | Byproduct of drinking water disinfection |
| 1,1,1-Trichloro-2-propanone | 0.4 ppb | 0 – 0.63 ppb | Byproduct of drinking water disinfection |
| Bromochloroacetonitrile | 0.39 ppb | 0 – 0.52 ppb | Byproduct of drinking water disinfection |
| Chloropicrin | 0.35 ppb | 0 – 0.66 ppb | Byproduct of drinking water disinfection |
| 1,1-Dichloro-2-propanone | 0.3 ppb | 0 – 0.58 ppb | Byproduct of drinking water disinfection |
| Ammonia | 0.28 ppm | 0.16 – 0.36 ppm | Disinfection with chloramines; wastes; fertilizers and natural processes |
| Chromium, Hexavalent | 0.15 ppb | 0.13 – 0.18 ppb | Manufacturing and weathering of natural deposits |
| Perchlorate | 0.1 ppb | 0.09 – 0.11 ppb | Naturally occurring and found as an impurity in hypochlorite solutions used for drinking water treatment |
| Metformin | 0.02 ppb | 0.01 – 0.03 ppb | Pharmaceutical |
Metformin: The CCR reports metformin detected at an average of 0.02 ppb. The distribution supplement's pharmaceutical panel lists metformin as NOT detected above its minimum reporting limit of 0.02 µg/L. The two documents disagree because the reported value sits exactly at the reporting limit. Both figures are reproduced as printed.
Voluntary monitoring panels
The utility tests for more than 500 substances to ensure safe water, increase understanding of how substances affect public health, and meet current and future regulations. The full list is published at milwaukee.gov/WaterQuality.
- Pharmaceuticals and personal care products (about 72 analytes): detected above the reporting limit — Erythromycin. Erythromycin was detected above the minimum reporting limit at a maximum of 0.02 µg/L. Acesulfame-K and sucralose were detected below their reporting limits. The panel covers hormones, antibiotics, analgesics, artificial sweeteners, DEET, caffeine and nicotine.
- Nitrosamines (about 9 analytes): none detected above reporting limits. Includes NDMA. None detected.
- Aldehydes (about 15 analytes): detected above the reporting limit — Formaldehyde. Formaldehyde reached a maximum of 7.00 µg/L against a 6.00 µg/L reporting limit. No regulatory limit exists for it in drinking water.
- Semi-volatile organic compounds (about 200 analytes): none detected above reporting limits. None detected above reporting limits.
- Volatile organic compounds (about 90 analytes): detected above the reporting limit — Bromodichloromethane, Bromoform, Chloroform, Chloromethane and Dibromochloromethane. All five detections are trihalomethane components, consistent with the TTHM figure in the regulated table.
Cryptosporidium and Giardia
MWW has remained committed to testing Lake Michigan source water for Cryptosporidium since 1993, even as many utilities and laboratories have discontinued this analysis. No Cryptosporidium or Giardia were detected in any of the water samples collected in 2025.
A brochure based on EPA and CDC guidance on lessening Cryptosporidium infection risk is available from the Customer Service Center at (414) 286-2830, or at milwaukee.gov/WaterQuality under Resource Links, 'Information for persons with weakened immune systems'.
Water hardness
8.1 grains per gallon · range 85.9–147 mg/L (USGS scale)
How hard is Milwaukee's water?
Milwaukee's water measures a median of 138 mg/L as calcium carbonate — roughly [8.1 grains per gallon](/tools/hardness-calculator). On the USGS scale that is hard water. Reported values ranged from 85.9 to 147 mg/L.
Across that range the water shifts from moderately hard to hard; the "hard" label applies to the median.
Components: calcium hardness median 90 mg/L (81.3 – 103), magnesium hardness median 47 mg/L (35 – 60.7).
Source: 2025 Distribution System Water Quality supplement, General Chemistry table.
At 138 mg/L you will see scale on fixtures and inside kettles. A whole-house softener will remove it, but that is a comfort and appliance-longevity decision rather than a necessary one.
Where your water comes from
Lake Michigan to your tap
Milwaukee draws its drinking water from Lake Michigan.
The system serves 17 communities in total — Milwaukee plus 16 suburban communities.
Retail service: Greenfield, Hales Corners, a portion of Franklin, Milwaukee, St. Francis and West Milwaukee. Wholesale service: Brown Deer, Butler, Greendale, Menomonee Falls, Mequon, New Berlin, Shorewood, Thiensville, Waukesha, Wauwatosa and West Allis.
Source water assessment
The most recent DNR Source Water Assessment is published under 'Resources' at milwaukee.gov/WaterQuality. See milwaukee.gov/WaterQuality.
How the water is treated
The treatment process, step by step (nine stages)
- Ozone disinfection. Ozone gas is bubbled through the incoming lake water. It destroys disease-causing microorganisms including Giardia and Cryptosporidium, controls taste and odour, and reduces the formation of chlorinated disinfection byproducts.
- Coagulation and flocculation. Aluminium sulfate neutralises the charge on microscopic particles, which are then gently mixed so suspended particles stick together to form floc.
- Sedimentation. Floc settles out and is removed from the water.
- Biologically active filtration. Water is slowly filtered through 24 inches of anthracite coal and 12 inches of crushed sand.
- Chlorine disinfection. After filtration, chlorine is added as a secondary disinfectant.
- Fluoridation. Fluoride at low levels helps prevent tooth decay.
- Clearwell storage. Treated water is stored in deep underground tanks and pumped as needed.
- Corrosion control. A food-grade phosphorus compound is added to control pipe corrosion, preventing lead and copper from leaching from plumbing into water.
- Chloramine protection. Ammonia converts the chlorine to chloramine, which maintains bacteriological protection through the distribution system.
Why Milwaukee's numbers look the way they do
Ozone as the primary disinfectant. Milwaukee's chlorinated disinfection byproducts are dramatically lower than comparable systems: TTHM at 8.6 ppb against an 80 ppb limit (11%) and HAA5 at 2.00 ppb against 60 (3%). For comparison, Durham reported 56 and 49 ppb, Cleveland 39.4 and 14.7.
The trade-off: Ozonation produces bromate instead. Milwaukee's bromate averaged 2.2 ppb against a 10 ppb running-annual-average limit, with individual distribution samples reaching 34.3 µg/L.
Beyond the legal minimum: Partnership for Safe Water — Distribution System Optimization Program
A voluntary programme that pushes utilities to continuously improve how they manage their system, balancing the benefits of disinfection against carefully limiting disinfection byproducts.
The utility holds the programme's Directors Award. The utility continues reporting and goal setting under the programme.
What you can do
Should you filter Milwaukee tap water?
Milwaukee's citywide numbers do not justify a filter on their own — nothing crosses half of a federal limit (the highest routine reading is Chlorine, Total at 40% of its residual disinfectant level). Whether you should filter depends on your address, not on the average. Lead compliance sampling here targets homes with lead service lines, and two of those homes still tested above the 15 ppb action level in 2023.
So the order of operations is: first check whether your property has a lead service line at milwaukee.gov/CheckAddress. If it does, the utility's own recommendation applies: "Filter drinking water using a filter certified to NSF/ANSI 53 standards and follow the filter instructions. Filtered water is recommended for children under 6 and those who are pregnant or breastfeeding."
Separately: at 138 mg/L the water is hard, so scale on fixtures is real — but a softener is a comfort and appliance decision, not a health one.
Advisories for specific groups
Infants and formula — the utility relays this guidance from CDC and American Academy of Pediatrics: "For infants up to six months of age, if fluoridated tap water is used to dilute infant formula, a parent may consider using a low-fluoride alternative water source. Ready-to-feed infant formula typically has little fluoride. There may be an increased chance of mild dental fluorosis if a child exclusively consumes formula reconstituted with fluoridated water."
Milwaukee fluoridates at a level not to exceed 0.7 mg/L, unchanged since 31 August 2012. Sources: CDC.gov, pediatrics.aappublications.org.
Immuno-compromised persons — including people undergoing chemotherapy, organ transplant recipients, people with HIV/AIDS or other immune system disorders, some elderly people, and infants — can be particularly at risk from infections and should seek advice about drinking water from their health care providers. EPA/CDC guidelines are available from the safe drinking water hotline at (800) 426-4791.
What this data does not tell you
Every number on this page describes water at the plants, in the mains, or as a system-wide statistic. None of it was measured in your building. If you want to know about your water rather than Milwaukee's, testing at your own tap is the only source.
Your pipes tell a different story
The data above shows what leaves the treatment plant—not what comes out of your faucet. Old pipes, lead solder, and building plumbing can add contaminants the city never tests for. Know exactly what's in your Milwaukee tap water.
Home test kits detect lead, bacteria, pesticides, and 100+ other contaminants. Results in 5-10 business days from certified labs.
If testing does point at a specific contaminant, our filter guides cover certifications and what to verify before buying.
Frequently asked questions
Sources and methodology
Primary sources
- *2025 Annual Water Quality Report* (Consumer Confidence Report), Milwaukee Water Works, PWSID WI2410100 — www.milwaukee.gov/awqr
- *2025 Distribution System Water Quality* — milwaukee.gov/WaterQuality
- EPA Safe Drinking Water Information System (SDWIS), PWSID WI2410100
- EPA PFAS National Primary Drinking Water Regulation and related Federal Register proposals — regulatory status checked 29 August 2026
How we compiled this
We do not test water. Every figure on this page is transcribed from documents published by Milwaukee Water Works or the EPA, and each is attributed to the document it came from. Where two published figures disagree, we show both and say so rather than choosing one.
Lead and copper values are 90th-percentile compliance statistics from the 2023 sampling round — older than the 2025 report. All samples were collected at customers' taps from properties with lead service lines. We state sample years next to values rather than presenting everything as current.
Author: TapWater.org Editorial Team — https://www.tapwater.org/about
Data current as of: the 2025 Consumer Confidence Report
This page presents publicly available regulatory data. It is not medical advice. Water quality varies by building and over time. For official information, contact Milwaukee Water Works at (414) 286-2830.
Last updated: 2026-09-11