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Otsego, WI Tap Water Quality 2026

Water quality report for Otsego, WI — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at Otsego's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Rio Waterworks PWSID: WI1110111 Updated: 2026 Q2
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1 violation currently open

Lead is 1.40 ppb, 9% of the action level. PFAS has never been sampled at this system.

D

Otsego earns a D for water quality

Graded on violations and lead, with state inspection findings. PFAS not tested.

Lead: 1.40 ppb — 9% of the federal action level
PFAS never sampled at this system
4 violations since 2015, 1 health-based
1 violation currently open
Otsego's lead level vs. all Wisconsin community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 1.40 ppb — 9% of the federal action level
✓ Lower lead than 67% of Wisconsin utilities
Population Served
~405 connections
Water Source
Groundwater
Drawn from wells — SDWIS source code GW
Active Violations
1
1 open of 4 since 2015

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
9% of EPA action level
1.40 ppb
Action level: 15 ppb
The 90th-percentile lead result is 1.40 ppb, 9% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
LEAD AND COPPER RULE REVISIONS TREATMENT TECHNIQUE — — 2024 Unaddressed
Public Notice OTHER — — 2024 Unaddressed
Lead and Copper Rule MONITORING AND REPORTING — TT 2024 Resolved
Groundwater Rule OTHER — — 2018 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

1 violation remains open, out of 4 recorded since 2015 (1 health-based).

About the Main Water System

Utility Rio Waterworks
PWSID WI1110111
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served
Service connections 405
Systems serving this area 1
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Otsego tap water safe to drink? ▼
No federal limit is exceeded on record. 1 violation(s) remain open. Lead is 1.40 ppb, 9% of the action level.
Does Otsego water have PFAS? ▼
This system has never been sampled for PFAS. EPA's national monitoring covered systems serving 3,300 people or more, so no results exist — which is not evidence that none is present.
Who supplies water to Otsego? ▼
Rio Waterworks (PWSID WI1110111). Groundwater. Drawn from wells — SDWIS source code GW
When was this system last inspected? ▼
It was last inspected on 2024-08-15. Inspectors recorded 1 significant deficiency.

What Should Otsego Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Follow the open violation
This system has an unresolved violation. Contact the supplier for its corrective-action schedule.

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