States › Wisconsin

Wisconsin Tap Water Quality 2026

EPA drinking water data for 1,279 cities across Wisconsin — covering lead levels, violation history, and compliance status.

Systems tracked: 723 Cities covered: 1,279 Updated: 2026 Q2
A

Wisconsin earns an A for overall water quality

1279 communities across 72 counties and 723 water systems. 97.5% have no open violations.

Median lead where detected: 2.06 ppb
16.1% of systems report lead as not detected — a state filing convention, not a water quality measure
PFAS tested at 29.0% of communities; 40 above the federal limit
Lead reported for 100.0% of communities
97.5% of communities have no open violations
Water Systems
723
Active community systems
Median Lead Level
2.06 ppb
14% of EPA action level
Fully Compliant
97.5%
of systems — no active violations
How we grade states Grades are based on actual EPA enforcement data — MCL violations and lead levels measured against the 15 ppb federal action level. We do not use MCLG-based detections, which are aspirational zero-tolerance goals that would make nearly every state look dangerous. Read our full methodology →

Best & Worst Cities in Wisconsin

✓ Cleanest Water
Sand Lake
Burnett County
0.0 ppb B
Lakeland
Barron County
1.2 ppb B
Alma
Buffalo County
0.0 ppb B
Morse
Ashland County
4.0 ppb B
Ashland
Ashland County
4.0 ppb B
Goetz
Chippewa County
1.2 ppb B
⚠ Needs Attention
Tomahawk
Lincoln County
1.8 ppb F
Bradley
Lincoln County
1.8 ppb F
Marshall
Rusk County
2.9 ppb F
Sheldon
Rusk County
2.9 ppb F
Fern
Florence County
8.1 ppb F
Glendale
Monroe County
2.4 ppb D

Water Quality by County

72 of 72
Sort:
CountySystemsLead LevelViolationsGrade
Dane County 54 2.9 ppb 0 A
Grant County 40 1.8 ppb 0 A
Dodge County 36 1.9 ppb 0 B
Waukesha County 35 2.8 ppb 0 A
Marathon County 34 2.4 ppb 0 B
Columbia County 33 2.0 ppb 0 B
Sauk County 30 1.8 ppb 0 A
Shawano County 27 0.9 ppb 0 A
Outagamie County 27 2.3 ppb 0 A
Sheboygan County 26 2.2 ppb 0 A

About Wisconsin Drinking Water

Wisconsin is served by 723 community water systems covering 1279 communities across 72 counties. 97.5% have no open violation on record.

Lead was detected in 1073 communities, with a median of 2.06 ppb — 14% of the federal action level. A further 206 reported none detected. That share is a state reporting convention rather than a measure of water quality, so it is stated separately rather than averaged in.

PFAS has been tested at 29.0% of communities here, and 40 are above the limits EPA set in 2024. Coverage matters: states that test more find more, so this figure is not comparable with a state that has tested less.

Frequently Asked Questions

Is Wisconsin tap water safe to drink? ▼
97.5% of communities have no open violation on record. 40 have PFAS above the federal limit set in 2024, which is the main open concern.
Does Wisconsin have a lead problem? ▼
9 water systems report a 90th-percentile lead result at or above the 15 ppb action level. The action level is a treatment trigger, not a legal maximum, and 206 communities report no detection at all.
How complete is the data for Wisconsin? ▼
Lead results are reported for 100.0% of communities and PFAS for 29.0%. Where a figure is missing it is shown as not reported rather than assumed safe.
How does Wisconsin compare with other states? ▼
We do not rank states against each other. Lead reporting completeness ranges from under 20% to 100% depending on the state, so a national ranking would compare filing practice rather than water quality.