Potosi, WI Tap Water Quality 2026

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

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

Main Utility: Potosi Waterworks PWSID: WI1220117 Updated: 2026 Q2

✅

No federal limits exceeded on record

Lead is 1.72 ppb, 11% of the action level and no violations are open. PFAS has never been sampled at this system.

Potosi earns a B for water quality

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

Lead: 1.72 ppb — 11% of the federal action level

PFAS never sampled at this system

6 violations since 2015, 2 health-based

No violations currently open

Potosi's lead level vs. all Wisconsin community water systems

0 ppb5 ppb10 ppb15 ppb

Lead level: 1.72 ppb — 11% of the federal action level

✓ Lower lead than 59% of Wisconsin utilities

Population Served

~265 connections

Water Source

Groundwater

Drawn from wells — SDWIS source code GW

Active Violations

6 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)

90th percentile of tap samples collected across the distribution system

11% of EPA action level

1.72 ppb

Action level: 15 ppb

The 90th-percentile lead result is 1.72 ppb, 11% 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)

Contaminant	Type	Measured	Limit	Period	Status
Stage 1 Disinfectants and Disinfection Byproducts Rule	TREATMENT TECHNIQUE	—	—	2024	Resolved
Lead and Copper Rule	MONITORING AND REPORTING	—	TT	2024	Resolved
Stage 1 Disinfectants and Disinfection Byproducts Rule	TREATMENT TECHNIQUE	—	—	2018	Resolved
Revised Total Coliform Rule	MONITORING FAILURE	—	—	2018	Resolved
Gross Alpha, Excl. Radon and U	MONITORING AND REPORTING	—	15 pCi/L	2018	Resolved
Lead and Copper Rule	MONITORING AND REPORTING	—	TT	2015	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

6 violations are on record since 2015, of which 2 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Potosi Waterworks

PWSID WI1220117

Water source Groundwater — Drawn from wells — SDWIS source code GW

Population served

Service connections 265

Systems serving this area 2

Regulator State primacy agency

Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Potosi tap water safe to drink? ▼

No federal limit is exceeded on record. No violations are currently open. Lead is 1.72 ppb, 11% of the action level.

Does Potosi 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 Potosi? ▼

Potosi Waterworks (PWSID WI1220117), one of 2 systems serving this area. Groundwater. Drawn from wells — SDWIS source code GW

When was this system last inspected? ▼

It was last inspected on 2024-06-24. No significant deficiencies were recorded.

What Should Potosi Residents Do?

Read your annual water report

Your supplier publishes a Consumer Confidence Report each July covering the prior year.

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.

Flush before drinking

If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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