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Thief River Falls

PWS ID: MN1570003 · Thief River Falls, Minnesota 56701

Thief River Falls serves 8,701 people in Thief River Falls, Minnesota using Surface Water water sources. It has 109 recorded EPA violations, including 68 health-based violations. PFAS "forever chemicals" were detected in UCMR5 testing (1 compound found).

Water Quality Snapshot: Thief River Falls

Thief River Falls is a local-owned community water system that delivers drinking water to 8,701 residents in Thief River Falls, Minnesota (Pennington County) through 3,503 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 109 total violations for this system , of which 68 (62%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 11 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Interim Enhanced Surface Water Treatment Rule, recorded in 60 violations (TT, health-based). Under EPA's UCMR5 PFAS monitoring program, 1 PFAS compound was detected in samples collected from this system, with a maximum reported concentration of 0.012 ppt. PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.

Across Minnesota, EPA tracks 6,557 public water systems serving 5,239,398 people, with 59,895 cumulative violations and 36,496 health-based violations on record. About 52% of systems in the state carry at least one violation, and state-wide the average per system is 9.1 violations. Thief River Falls's 109 violations sit above the Minnesota average. Statewide, 149 of 196 UCMR5-tested systems have reported PFAS detections (76%). All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

PFAS Detected

1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.

Population Served
8,701
Total Violations
109
Health-Based Violations
68
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
3,503
County
Pennington
School/Daycare
No
MCL Violations
0
Monitoring Violations
11
Treatment Tech Violations
68

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Interim Enhanced Surface Water Treatment Rule TT 60 2025
Surface Water Treatment Rule TT 8 2004
Interim Enhanced Surface Water Treatment Rule MR 8 2017
Lead and Copper Rule MR 3 2021

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 4 of 120 samples detected PFAS.

Contaminant Date Result MRL Status
4:2 FTS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHxS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFNA 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFOS 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFOA 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFDA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFDoA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHxA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFUnA 7/26/2023 <0.002 µg/L 0.002 µg/L Not Detected
11Cl-PF3OUdS 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
9Cl-PF3ONS 7/26/2023 <0.002 µg/L 0.002 µg/L Not Detected
ADONA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHpA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFBA 7/26/2023 0.0096 µg/L 0.005 µg/L Detected
6:2 FTS 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFMBA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFMPA 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFPeA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFEESA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFPeS 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFHpS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFBS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
NFDHA 7/26/2023 <0.02 µg/L 0.02 µg/L Not Detected
lithium 7/26/2023 <9 µg/L 9 µg/L Not Detected
NMeFOSAA 7/26/2023 <0.006 µg/L 0.006 µg/L Not Detected
NEtFOSAA 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFTrDA 7/26/2023 <0.007 µg/L 0.007 µg/L Not Detected
PFTA 7/26/2023 <0.008 µg/L 0.008 µg/L Not Detected
HFPO-DA 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
8:2 FTS 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFHpS 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
6:2 FTS 4/12/2023 <0.005 µg/L 0.005 µg/L Not Detected
4:2 FTS 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
8:2 FTS 4/12/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFMPA 4/12/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFPeA 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFMBA 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFEESA 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFPeS 4/12/2023 <0.004 µg/L 0.004 µg/L Not Detected
lithium 4/12/2023 <9 µg/L 9 µg/L Not Detected
PFBA 4/12/2023 0.0120 µg/L 0.005 µg/L Detected
NFDHA 4/12/2023 <0.02 µg/L 0.02 µg/L Not Detected
PFOS 4/12/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFTrDA 4/12/2023 <0.007 µg/L 0.007 µg/L Not Detected
NEtFOSAA 4/12/2023 <0.005 µg/L 0.005 µg/L Not Detected
NMeFOSAA 4/12/2023 <0.006 µg/L 0.006 µg/L Not Detected
PFHxA 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFTA 4/12/2023 <0.008 µg/L 0.008 µg/L Not Detected
PFHpA 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFBS 4/12/2023 <0.003 µg/L 0.003 µg/L Not Detected

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records — or to file a complaint, request a Consumer Confidence Report, or check current monitoring status — go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Thief River Falls.

Federal Source of Truth

EPA SDWIS — Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID MN1570003 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Minnesota Drinking Water Authority

Minnesota's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.

Find MN regulator via EPA SDWIS

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2025 Interim Enhanced Surface Water Treatment Rule TT 60 SDWIS / MN1570003 / 0300
2021 Lead and Copper Rule MR 3 SDWIS / MN1570003 / 5000
2017 Interim Enhanced Surface Water Treatment Rule MR 8 SDWIS / MN1570003 / 0300
2004 Surface Water Treatment Rule TT 8 SDWIS / MN1570003 / 0200

How Thief River Falls Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Thief River Falls Minnesota avg Federal benchmark
Total violations 109 9.1 SDWA compliance — any non-zero count is a recorded breach
Health-based violations 68 5.6 Indicates a contaminant exceeded a federal MCL
PFAS detection 1 compound 76% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 8,701 799 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 6,557 regulated public water systems in Minnesota.

Federal MCL reference — Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Thief River Falls water safe to drink? ▼
Thief River Falls (PWS ID: MN1570003) has 109 recorded violations in the EPA SDWIS database. PFAS contamination has been detected in UCMR5 testing, with 1 PFAS compound found. This system serves 8,701 people using Surface Water sources.
How many people does Thief River Falls serve? ▼
Thief River Falls serves 8,701 people in Thief River Falls, Minnesota. It is a Local-owned system using Surface Water water sources with 3,503 service connections.
What type of violations does Thief River Falls have? ▼
Thief River Falls has 109 total violations: 68 health-based violations (MCL exceedances or treatment failures), 11 monitoring/reporting violations, and 68 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Thief River Falls water? ▼
Yes. UCMR5 testing detected 1 PFAS compound in Thief River Falls's water supply: PFBA. PFAS are persistent "forever chemicals" that do not break down in the environment.
What water source does Thief River Falls use? ▼
Thief River Falls uses Surface Water as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

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Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.

Read our methodology — how this data is sourced, computed, and verified.

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Data sourced from $official public datasets. See our methodology for details. Retrieved and formatted by Kiznis Studio Editorial