States ›Wisconsin ›Grant County ›Potosi

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: Tennyson Waterworks PWSID: WI1220120 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 3.77 ppb, 25% of the action level and no violations are open. PFAS has never been sampled at this system.

B

Potosi earns a B for water quality

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

Lead: 3.77 ppb — 25% of the federal action level
PFAS never sampled at this system
8 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: 3.77 ppb — 25% of the federal action level
✓ Lower lead than 27% of Wisconsin utilities
Population Served
282
~135 connections
Water Source
Groundwater
Drawn from wells — SDWIS source code GW
Active Violations
0
8 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
25% of EPA action level
3.77 ppb
Action level: 15 ppb
The 90th-percentile lead result is 3.77 ppb, 25% 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 MONITORING AND REPORTING — TT 2025 Resolved
Stage 1 Disinfectants and Disinfection Byproducts Rule TREATMENT TECHNIQUE — — 2024 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2024 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2023 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

8 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 Tennyson Waterworks
PWSID WI1220120
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served 282
Service connections 135
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 3.77 ppb, 25% 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? ▼
Tennyson Waterworks (PWSID WI1220120), 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?

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

Nearby Cities in Wisconsin

Platteville, Wi Tap Water Quality 2026 Grant Lancaster, Wi Tap Water Quality 2026 Grant Fennimore, Wi Tap Water Quality 2026 Grant Boscobel, Wi Tap Water Quality 2026 Grant Cuba City, Wi Tap Water Quality 2026 Grant Muscoda, Wi Tap Water Quality 2026 Grant