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Jefferson, WI Tap Water Quality 2026

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

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

Main Utility: Jefferson Waterworks PWSID: WI1280104 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 3.50 ppb, 23% of the action level and no violations are open. No PFAS was detected.

B

Jefferson earns a B for water quality

Graded on violations, lead, and PFAS, with state inspection findings.

Lead: 3.50 ppb — 23% of the federal action level
PFAS tested, none detected
8 violations since 2015, 7 health-based
No violations currently open
Jefferson's lead level vs. all Wisconsin community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 3.50 ppb — 23% of the federal action level
✓ Lower lead than 30% of Wisconsin utilities
Population Served
97
~3072 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
23% of EPA action level
3.50 ppb
Action level: 15 ppb
The 90th-percentile lead result is 3.50 ppb, 23% 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 2024 Resolved
Combined Radium (-226 and -228) MCL EXCEEDANCE 6.83 PCI/L 5 pCi/L 2024 Archived
Combined Radium (-226 and -228) MCL EXCEEDANCE 7.05 PCI/L 5 pCi/L 2024 Archived
Combined Radium (-226 and -228) MCL EXCEEDANCE 7.81 PCI/L 5 pCi/L 2023 Archived
Combined Radium (-226 and -228) MCL EXCEEDANCE 7.73 PCI/L 5 pCi/L 2023 Archived
Combined Radium (-226 and -228) MCL EXCEEDANCE 5.79 PCI/L 5 pCi/L 2023 Archived
Combined Radium (-226 and -228) MCL EXCEEDANCE 6.19 PCI/L 5 pCi/L 2023 Archived
Combined Radium (-226 and -228) MCL EXCEEDANCE 5.7525 MG/L 5 pCi/L 2022 Archived
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 7 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Jefferson Waterworks
PWSID WI1280104
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served 97
Service connections 3,072
Systems serving this area 2
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Jefferson tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 3.50 ppb, 23% of the action level.
Does Jefferson water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Jefferson? ▼
Jefferson Waterworks (PWSID WI1280104), 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 2025-12-23. No significant deficiencies were recorded.

What Should Jefferson 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.

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