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Federal water data

County water report

Milwaukee County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Milwaukee County, Wisconsin.

Water grade

A

Water score

71.5

State rank

#2

of 71

Health violations

3

EPA SDWIS, 5-year lookback

Watershed impaired

28.9%

180 water bodies assessed

Monitoring sites

515

574,425 recent measurements

Live streamflow

No gauge

MILWAUKEE RIVER AT MOUTH AT MILWAUKEE, WI

Water at a glance

Key Water Indicators for Milwaukee County

EPA SDWIS

Safety Grade

A

Score: 71.5 / 100

EPA SDWIS

Active Violations

3

5-year health-based lookback

EPA ATTAINS

Watershed Health

29% impaired

180 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

MILWAUKEE RIVER AT MOUTH AT MILWAUKEE, WI

EPA WQP

Monitoring Sites

515

574,425 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

71.5/100

Health violations

3

Health-based violations

Violations per 100K served

0.3

Population-normalized SDWIS rate

Data center water stress

Milwaukee County has 3 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #85 nationally by combining its water score with mapped data center density.

DCWSIThe Data Center Water Stress Index: 60% the county's water-system stress plus 40% how concentrated data centers already are, scored 0-100. Higher means data-center density and water pressure overlap more here.

67.3

0-100 index

Facility count

3

61.1 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+21.5

Compared with US county median

Named operators

Potawatomi Business Development Corporation

Mapped facilities

  • Data Holdings Data Center

    Milwaukee · Potawatomi Business Development Corporation

    OSM

  • Expedient Milwaukee

    Franklin

    OSM

  • TierPoint Milwaukee

    Facility details limited

    OSM
See the Milwaukee County data-center reportReview methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in Milwaukee County.

1 MW1,000 MW
40%100%
799K gallons/dayModerate Impact

Your facility would use 14.2% of this county's industrial water baseline — manageable but worth monitoring against drought trends.

14.2% of county industrial baseline4.84 Mgal/day remaining headroom

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding Milwaukee County’s Water

Drinking Water Quality Overview

EPA SDWIS

Milwaukee County earns an A grade for drinking water quality, scoring 71.5 out of 100. Over the past five years, EPA SDWIS records 3 health-based violations — a small cluster that warrants attention.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A notable 28.9% of assessed waterways carry an impairment designation (52 of 180 water bodies) across Milwaukee County's watersheds. The leading impairment causes are phosphorus, total and chloride. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Milwaukee County has extensive coverage with 515 active monitoring sites with 574,425 recent measurements on record. Predominant monitoring categories include physical and nutrient. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for Milwaukee County

Water Verdict

Milwaukee County, Wisconsin 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. Separately, EPA ATTAINS assessments cover 180 water bodies in the county's watershed, with 28.9% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance.

Violation Context

EPA SDWIS records for Milwaukee County, Wisconsin show 3 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 0.3 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. This compliance record sits alongside an unusually deep monitoring archive: 574,425 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in Milwaukee County earns a Grade A overall with a small number of isolated health violations in the recent record. Milwaukee County's drinking-water compliance score is 71.5 out of 100. The violation rate for Milwaukee County is 0.3 per 100,000 people served. These violations were likely resolved quickly; Grade A reflects a strong multi-year compliance trend. Reviewing the most recent Consumer Confidence Report will show exactly which systems were affected and what corrective action was taken. With 515 active water-quality monitoring sites in Milwaukee County, data coverage is strong. Phosphorus, Total is the leading impairment cause in Milwaukee County's watershed. A pipeline streamflow snapshot from the MILWAUKEE RIVER gauge is also available on this page.

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.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Milwaukee County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Phosphorus (excess nutrients)

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 2

    Chloride

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 3

    Fecal coliform bacteria

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Milwaukee County

EPA How's My Waterway

Interactive watershed health data for Milwaukee County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Milwaukee County

Consumer Confidence Reports (WI)

Annual water quality reports from utilities in Wisconsin

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).

Free tool

Estimate Your Water Costs

Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Milwaukee County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

Try the full calculator →

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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 streamflow snapshots 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 and 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 Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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