F4/100
Thief River Falls — Water Quality Report 2026
Serving 8,701 people · Minnesota
Water Source
Surface Water
County
—
System ID
MN1570003
Violations
21
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.007 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
1
Violation (last 5yr)
1
Unresolved
1
Health-Related
TIER 1 — URGENTUnresolved
Violation related to Nitrate
When: January 1, 2025 – January 31, 2025Rule: Surface Water Treatment RuleEnforcement: Informal — resolved cooperativelyVerify 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 Thief River Falls
Is Thief River Falls water safe to drink?
Thief River Falls water receives a grade of F (4/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 21 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has Thief River Falls detected?
31 contaminants were tested in Thief River Falls's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does Thief River Falls have any EPA violations?
Yes, Thief River Falls has 21 EPA violation(s) on record, with the most recent in 2025. Violation types include TT, MR. 18 are health-based violations.
How many people does Thief River Falls serve?
Thief River Falls serves approximately 8,701 people, Minnesota.
What type of water does Thief River Falls provide?
Thief River Falls sources its water from surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is MN1570003.
How does Thief River Falls compare to other utilities in Minnesota?
Thief River Falls scores 4/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Minnesota state page for a full comparison of water systems.