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Oneida County, WI Water Quality

Water quality data for 4 public water systems serving Oneida County, Wisconsin — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 4 water systems · 10 cities
⚠️
Caution Advised — Some Systems Need Attention

Some systems have elevated lead levels or active violations. Check your specific city below.

C

Oneida County Earns a C

Oneida County: 10 communities across 4 water systems. 100.0% have no open violations.

  • Median lead where detected: 1.00 ppb
  • 8 communities with a lead detection, 2 reporting none detected
  • 5 communities with PFAS above the federal limit
  • 7 with significant inspection deficiencies
  • 100.0% of communities have no open violations
1 ppb
Median Lead Level
County-wide, 90th percentile
4
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
  • Lake Tomahawk
    Not detected
    No federal limits exceeded on record
    B
  • Cassian
    Not detected
    No federal limits exceeded on record
    B
  • Three Lakes
    11.20 ppb
    2 health-based violations since 2015
    B
  • Woodruff
    2.20 ppb
    1 significant inspection deficiency
    B
  • Minocqua
    2.20 ppb
    1 significant inspection deficiency
    B
⚠ Needs Attention
  • Rhinelander
    1.00 ppb
    PFAS above the limit at 1 of 2 sampling points
    C
  • Pine Lake
    1.00 ppb
    PFAS above the limit at 1 of 2 sampling points
    C
  • Pelican
    1.00 ppb
    PFAS above the limit at 1 of 2 sampling points
    C
  • Crescent
    1.00 ppb
    PFAS above the limit at 1 of 2 sampling points
    C
  • Newbold
    1.00 ppb
    PFAS above the limit at 1 of 2 sampling points
    C
County Lead Level — Median 1 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1 ppb — 6.7% of the federal action level
Systems by Lead Level
Under 5 ppb
7
10 – 15 ppb
1
No Data
2

All Cities in Oneida County

Rhinelander 1.00 ppb C
Woodruff 2.20 ppb B
Minocqua 2.20 ppb B
Three Lakes 11.20 ppb B
Pine Lake 1.00 ppb C
Lake Tomahawk Not detected B
Pelican 1.00 ppb C
Crescent 1.00 ppb C
Newbold 1.00 ppb C
Cassian Not detected B
Showing 10 cities
No active violations Active violations

About Oneida County Drinking Water

Oneida County is served by 4 water systems covering 10 communities. No community here has an open violation on record.

Of the communities reporting lead results, 8 recorded a detection, with a median of 1.00 ppb — 7% of the federal action level. 2 reported none detected, which means below the laboratory limit rather than an absence of lead.

5 of 10 communities have PFAS above the limits EPA set in 2024, measured as a running annual average at each sampling point. State inspectors recorded significant deficiencies at 7 of them.

Frequently Asked Questions

Is Oneida County tap water safe to drink?▼
No community in Oneida County has an open violation on record. 5 of 10 have PFAS above the federal limit, which is the main open concern.
What is the lead level in Oneida County?▼
Among communities with a detection the median is 1.00 ppb, 7% of the 15 ppb action level. 2 reported none detected and 0 reported no result.
How many water systems serve Oneida County?▼
4 community water systems serve 10 communities here.
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