waterbycounty
EPA SDWIS

Milwaukee County Water Quality

Milwaukee County, Wisconsin

Water Grade

A

Water Score

71.5

Violations

3

State Rank

#2

of 71 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

A

Based on EPA compliance history and violation data

Water Score

71.5/100

Higher = better quality

Health Violations

3

Health-based violations

Violation Rate

0.3%

Systems with violations

Water Advisory: Milwaukee County

Water Verdict

Milwaukee County receives a good water quality assessment with a grade of A and a score of 71.5 out of 100. While the water supply is generally safe, occasional monitoring gaps or minor contaminant detections may occur.

Violation Context

Milwaukee County has recorded 3 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 0.3 violations per 1,000 residents, this rate is relatively low compared to many U.S. counties.

Consumer Guidance

Tap water in Milwaukee County is generally safe to drink based on available data. Residents should still review their utility's annual Consumer Confidence Report for transparency on detected contaminants. With 3 recorded health violations, staying informed about utility communications and boil-water notices is especially important. For long-term peace of mind, request your utility's latest Consumer Confidence Report and consider independent water testing if you have specific health concerns.

Regional Context

Milwaukee County has better water quality than the average county in Wisconsin. Its water score is 32 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

28.9%

52 of 180 assessed

Some impairment

Top Impairment Causes

  • 1

    PHOSPHORUS, TOTAL

  • 2

    CHLORIDE

  • 3

    FECAL COLIFORM

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state — counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

515

Active in the past 5 years

Measurements Recorded

574K

574,425 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Major, Non-metals

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

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Frequently Asked Questions

What is the water quality in Milwaukee County, Wisconsin?
Milwaukee County, Wisconsin has a drinking-water quality grade of A with a score of 71.5/100, based on EPA SDWIS compliance data. The county has 3 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and live streamflow are reported separately on this page.
Are there any water violations in Milwaukee County?
Milwaukee County has 3 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.
How healthy are the watersheds in Milwaukee County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 28.9% of Milwaukee County's 180 assessed water bodies are classified as impaired (52 impaired). The top reported causes are PHOSPHORUS, TOTAL, CHLORIDE, FECAL COLIFORM. Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in Milwaukee County?
EPA's Water Quality Portal records 574,425 measurements from 515 monitoring sites in Milwaukee County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Major, Non-metals. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.
How does Milwaukee County water compare to the Wisconsin average?
Milwaukee County's SDWIS water quality score of 71.5/100 is higher than the Wisconsin state average of 39.5. The average water quality grade across Wisconsin is F, based on data from 71 counties with available SDWIS data.
Is tap water safe to drink in Milwaukee County?
Based on EPA SDWIS data, Milwaukee County has a water quality grade of A (71.5/100). This indicates good to excellent water quality with strong SDWIS compliance. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).
Does Milwaukee County have clean drinking water?
Milwaukee County has 3 health-based drinking water violations according to EPA records. With a water quality score of 71.5/100 and grade A, the county's drinking water has had some compliance issues but continues to be monitored. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Milwaukee County rank for water quality in Wisconsin?
Milwaukee County ranks #2 out of 71 counties in Wisconsin by SDWIS water quality score (1 = best). With a score of 71.5/100, it falls in the top third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Wood County

Wisconsin

B

67.5

Water score

Portage County

Wisconsin

B

67.3

Water score

Outagamie County

Wisconsin

B

66.2

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments — state-reported, EPA-finalized.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP) — federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

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