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D32/100

JEFFERSON WATERWORKS — Water Quality Report 2026

Serving 7,926 people · Wisconsin

Water Source
Groundwater
County
—
System ID
WI1280104
Violations
17

Contaminant Test Results

1 contaminant above EPA health goals
ContaminantDetectedLimit (MCL)Status
Lead (90th percentile)
0.004 mg/L0.015 mg/LAbove Goal

EPA Violation History

8

Violations (last 5yr)

7

Unresolved

7

Health-Related

TIER 3Resolved

Monitoring / Reporting Violation

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: October 1, 2024 – November 19, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: April 1, 2024 – June 30, 2024Enforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: January 1, 2024 – March 31, 2024Enforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: October 1, 2023 – December 31, 2023Enforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: July 1, 2023 – September 30, 2023Enforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: April 1, 2023 – June 30, 2023Enforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: January 1, 2023 – March 31, 2023Enforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved

Exceeded the Maximum Contaminant Level (running average)

When: October 1, 2022 – December 31, 2022Enforcement: Formal — state order issuedVerify on EPA.gov

Understanding violation severity

Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.

Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly

Frequently Asked Questions About JEFFERSON WATERWORKS

Is JEFFERSON WATERWORKS water safe to drink?

JEFFERSON WATERWORKS water receives a grade of D (32/100), which is considered poor. 0 contaminant(s) exceed EPA legal limits and 17 violation(s) are on record. Customers may want to consider using a water filter.

What contaminants has JEFFERSON WATERWORKS detected?

31 contaminants were tested in JEFFERSON WATERWORKS's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).

Does JEFFERSON WATERWORKS have any EPA violations?

Yes, JEFFERSON WATERWORKS has 17 EPA violation(s) on record, with the most recent in 2024. Violation types include MR, MCL, Other. 12 are health-based violations.

How many people does JEFFERSON WATERWORKS serve?

JEFFERSON WATERWORKS serves approximately 7,926 people, Wisconsin. The system provides water to 1 community: Jefferson.

What type of water does JEFFERSON WATERWORKS provide?

JEFFERSON WATERWORKS sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is WI1280104.

How does JEFFERSON WATERWORKS compare to other utilities in Wisconsin?

JEFFERSON WATERWORKS scores 32/100 with a grade of D (poor). This score suggests significant water quality concerns relative to other utilities. Visit our Wisconsin state page for a full comparison of water systems.

Cities Served

Jefferson