States › Wisconsin › Dane County

Dane County, WI Water Quality

Water quality data for 31 public water systems serving Dane County, Wisconsin — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 31 water systems · 54 cities
✅
Excellent — All Systems Performing Well

Water quality across the county is outstanding with minimal violations and very low lead levels.

A

Dane County Earns a A

Dane County: 54 communities across 31 water systems. 100.0% have no open violations.

  • Median lead where detected: 2.85 ppb
  • 52 communities with a lead detection, 2 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 8 with significant inspection deficiencies
  • 100.0% of communities have no open violations
2.85 ppb
Median Lead Level
County-wide, 90th percentile
31
Water Systems
Active CWS & NTNCWS
100%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • Rutland
    4.20 ppb
    No federal limits exceeded on record
    A
  • Dane
    3.10 ppb
    No federal limits exceeded on record
    B
  • Fitchburg
    2.30 ppb
    No federal limits exceeded on record
    A
  • Waunakee
    1.70 ppb
    No federal limits exceeded on record
    A
  • Stoughton
    4.20 ppb
    No federal limits exceeded on record
    A
⚠ Needs Attention
  • Middleton
    4.00 ppb
    1 significant inspection deficiency
    B
  • Middleton
    4.00 ppb
    1 significant inspection deficiency
    B
  • Cambridge
    1.16 ppb
    2 significant inspection deficiencies
    B
  • DeForest
    5.95 ppb
    1 health-based violation since 2015
    B
  • Vienna
    5.95 ppb
    1 health-based violation since 2015
    B
County Lead Level — Median 2.85 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 2.85 ppb — 19% of the federal action level
Systems by Lead Level
Under 5 ppb
49
5 – 10 ppb
3
No Data
2

All Cities in Dane County

Madison 1.80 ppb A
Sun Prairie 2.80 ppb A
Fitchburg 2.30 ppb A
Middleton 4.00 ppb B
Verona 2.86 ppb A
Waunakee 1.70 ppb A
Stoughton 4.20 ppb A
Oregon 4.97 ppb A
DeForest 5.95 ppb B
McFarland 2.10 ppb A
Monona 2.83 ppb B
Mount Horeb 3.00 ppb A
Cottage Grove 2.33 ppb A
Cross Plains 4.80 ppb A
Marshall 0.33 ppb A
Windsor 5.50 ppb B
Belleville 1.50 ppb B
Deerfield 1.72 ppb B
Shorewood Hills 1.72 ppb B
Middleton 4.00 ppb B
Mazomanie Not detected B
Burke 2.80 ppb A
Cambridge 1.16 ppb B
Brooklyn 0.78 ppb B
Black Earth 2.40 ppb B
Maple Bluff 2.79 ppb B
Dane 3.10 ppb B
Cottage Grove 2.33 ppb A
Blue Mounds 0.91 ppb B
Verona 2.86 ppb A
Dunkirk 4.20 ppb A
Westport 1.70 ppb A
Pleasant Springs 4.20 ppb A
Dunn 4.20 ppb A
Blooming Grove 2.10 ppb A
Springfield 3.81 ppb B
Deerfield 3.06 ppb B
Bristol 3.60 ppb B
Mazomanie Not detected B
Oregon 4.97 ppb A
Christiana 3.06 ppb B
Montrose 1.50 ppb B
Sun Prairie 2.33 ppb A
Madison 1.80 ppb A
Medina 0.33 ppb A
Vienna 5.95 ppb B
Blue Mounds 3.00 ppb A
Springdale 3.00 ppb A
Albion 2.76 ppb A
Dane 3.10 ppb B
Rutland 4.20 ppb A
Black Earth 2.40 ppb B
Berry 4.80 ppb A
Cross Plains 4.80 ppb A
Showing 54 cities
No active violations Active violations

About Dane County Drinking Water

Dane County is served by 31 water systems covering 54 communities. No community here has an open violation on record.

Of the communities reporting lead results, 52 recorded a detection, with a median of 2.85 ppb — 19% of the federal action level. 2 reported none detected, which means below the laboratory limit rather than an absence of lead.

No community here has PFAS above the federal limit on record. State inspectors recorded significant deficiencies at 8 of them.

Frequently Asked Questions

Is Dane County tap water safe to drink?▼
No community in Dane County has an open violation on record. No community has PFAS above the federal limit on record.
What is the lead level in Dane County?▼
Among communities with a detection the median is 2.85 ppb, 19% of the 15 ppb action level. 2 reported none detected and 0 reported no result.
How many water systems serve Dane County?▼
31 community water systems serve 54 communities here.
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