F0/100
THERESA WATERWORKS — Water Quality Report 2026
Serving 1,262 people · Wisconsin
Water Source
Groundwater
County
—
System ID
WI1140154
Violations
106
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | < 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
3
Violations (last 5yr)
2
Unresolved
2
Health-Related
TIER 2Resolved
Violation related to Nitrite
When: September 3, 2025 – September 25, 2025Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
TIER 2Unresolved
Treatment technique violation
TIER 3Unresolved
Disinfection byproduct treatment technique failure
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 THERESA WATERWORKS
Is THERESA WATERWORKS water safe to drink?
THERESA WATERWORKS water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 106 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has THERESA WATERWORKS detected?
1 contaminants were tested in THERESA WATERWORKS's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does THERESA WATERWORKS have any EPA violations?
Yes, THERESA WATERWORKS has 106 EPA violation(s) on record, with the most recent in 2025. Violation types include TT, Other, MR. 3 are health-based violations.
How many people does THERESA WATERWORKS serve?
THERESA WATERWORKS serves approximately 1,262 people, Wisconsin. The system provides water to 1 community: Theresa.
What type of water does THERESA WATERWORKS provide?
THERESA WATERWORKS sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is WI1140154.
How does THERESA WATERWORKS compare to other utilities in Wisconsin?
THERESA WATERWORKS scores 0/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Wisconsin state page for a full comparison of water systems.