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Community Water System · PWS MT0000274

Libby City Of

Libby, Montana 59923 - drinking water served from surface water sources to 4,892 people, tracked in EPA SDWIS and UCMR5.

4,892
People served
341
EPA violations
100
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 341 drinking-water violations at Libby City Of, 29% of them health-based - above the Montana per-system average.

341
Total EPA violations on record
29%
Health-based (MCL / treatment failure)
4,892
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Libby City Of

Libby City Of is a local-owned community water system that delivers drinking water to 4,892 residents in Libby, Montana (Lincoln County) through 1,957 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 341 total violations for this system , of which 100 (29%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 221 monitoring and reporting violations are on file. The most recent violation on record dates to 2022.

The most frequently cited contaminant at this system is Surface Water Treatment Rule, recorded in 60 violations (TT, health-based). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across Montana, EPA tracks 2,263 public water systems serving 1,112,267 people, with 297,270 cumulative violations and 25,922 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 131.4 violations. Statewide, 28 of 45 UCMR5-tested systems have reported PFAS detections (62.2%).

Libby City Of's 341 violations sit above the Montana average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
4,892
Total Violations
341
Health-Based Violations
100
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
1,957
County
Lincoln
School/Daycare
No
MCL Violations
0
Monitoring Violations
221
Treatment Tech Violations
100

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Surface Water Treatment Rule TT 60 2013
CARBON, TOTAL MR 45 2004
Interim Enhanced Surface Water Treatment Rule TT 37 2022
Coliform (TCR) MR 9 2002
Arsenic MR 9 2014
Consumer Confidence Rule Other 7 2019
Lead and Copper Rule MR 6 2011
Xylenes, Total MR 6 2021
DICHLOROMETHANE MR 6 2021
o-Dichlorobenzene MR 6 2021
p-Dichlorobenzene MR 6 2021
Vinyl chloride MR 6 2021
1,1-Dichloroethylene MR 6 2021
1,2-Dichloroethane MR 6 2021
1,1,1-Trichloroethane MR 6 2021
Carbon tetrachloride MR 6 2021
1,2-Dichloropropane MR 6 2021
CHLOROBENZENE MR 6 2021
1,2,4-Trichlorobenzene MR 6 2021
cis-1,2-Dichloroethylene MR 6 2021
trans-1,2-Dichloroethylene MR 6 2021
Trichloroethylene MR 6 2021
Tetrachloroethylene MR 6 2021
Styrene MR 6 2021
1,1,2-Trichloroethane MR 6 2021
Benzene MR 6 2021
Ethylbenzene MR 6 2021
Toluene MR 6 2021
TTHM MR 3 2006
Total Haloacetic Acids (HAA5) MR 3 2006

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 87 samples detected PFAS.

Contaminant Date Result MRL Status
PFDoA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFPeS 8/18/2025 <4.00 ppt 4.00 ppt Not Detected
NFDHA 8/18/2025 <20.00 ppt 20.00 ppt Not Detected
PFEESA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFMBA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 8/18/2025 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 8/18/2025 <5.00 ppt 5.00 ppt Not Detected
PFBA 8/18/2025 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 8/18/2025 <5.00 ppt 5.00 ppt Not Detected
ADONA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 8/18/2025 <2.00 ppt 2.00 ppt Not Detected
PFMPA 8/18/2025 <4.00 ppt 4.00 ppt Not Detected
PFHpS 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFHxA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFPeA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFDA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFBS 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFOA 8/18/2025 <4.00 ppt 4.00 ppt Not Detected
PFOS 8/18/2025 <4.00 ppt 4.00 ppt Not Detected
PFNA 8/18/2025 <4.00 ppt 4.00 ppt Not Detected
PFHxS 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
PFHpA 8/18/2025 <3.00 ppt 3.00 ppt Not Detected
NMeFOSAA 8/18/2025 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 8/18/2025 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 8/18/2025 <7.00 ppt 7.00 ppt Not Detected
PFTA 8/18/2025 <8.00 ppt 8.00 ppt Not Detected
PFUnA 8/18/2025 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 8/18/2025 <5.00 ppt 5.00 ppt Not Detected
PFHpS 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 5/20/2025 <5.00 ppt 5.00 ppt Not Detected
PFMPA 5/20/2025 <4.00 ppt 4.00 ppt Not Detected
PFPeA 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
PFMBA 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
PFEESA 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
PFNA 5/20/2025 <4.00 ppt 4.00 ppt Not Detected
PFPeS 5/20/2025 <4.00 ppt 4.00 ppt Not Detected
PFBA 5/20/2025 <5.00 ppt 5.00 ppt Not Detected
NFDHA 5/20/2025 <20.00 ppt 20.00 ppt Not Detected
NMeFOSAA 5/20/2025 <6.00 ppt 6.00 ppt Not Detected
PFDoA 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
PFDA 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
PFOA 5/20/2025 <4.00 ppt 4.00 ppt Not Detected
PFOS 5/20/2025 <4.00 ppt 4.00 ppt Not Detected
PFHpA 5/20/2025 <3.00 ppt 3.00 ppt Not Detected
PFUnA 5/20/2025 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 5/20/2025 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 5/20/2025 <5.00 ppt 5.00 ppt Not Detected
PFBS 5/20/2025 <3.00 ppt 3.00 ppt 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 Libby City Of.

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 MT0000274 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Montana Drinking Water Authority

Montana'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 MT 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
2022 Interim Enhanced Surface Water Treatment Rule TT 37 SDWIS / MT0000274 / 0300
2022 Long Term 2 Enhanced Surface Water Treatment Rule TT 3 SDWIS / MT0000274 / 0800
2021 Xylenes, Total MR 6 SDWIS / MT0000274 / 2955
2021 DICHLOROMETHANE MR 6 SDWIS / MT0000274 / 2964
2021 o-Dichlorobenzene MR 6 SDWIS / MT0000274 / 2968
2021 p-Dichlorobenzene MR 6 SDWIS / MT0000274 / 2969
2021 Vinyl chloride MR 6 SDWIS / MT0000274 / 2976
2021 1,1-Dichloroethylene MR 6 SDWIS / MT0000274 / 2977
2021 1,2-Dichloroethane MR 6 SDWIS / MT0000274 / 2980
2021 1,1,1-Trichloroethane MR 6 SDWIS / MT0000274 / 2981
2021 Carbon tetrachloride MR 6 SDWIS / MT0000274 / 2982
2021 1,2-Dichloropropane MR 6 SDWIS / MT0000274 / 2983
2021 CHLOROBENZENE MR 6 SDWIS / MT0000274 / 2989
2021 1,2,4-Trichlorobenzene MR 6 SDWIS / MT0000274 / 2378
2021 cis-1,2-Dichloroethylene MR 6 SDWIS / MT0000274 / 2380

How Libby City Of Compares

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

Metric Libby City Of Montana avg Federal benchmark
Total violations 341 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 100 11.5 Indicates a contaminant exceeded a federal MCL
PFAS detection None 62.2% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 4,892 492 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,263 regulated public water systems in Montana.

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 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Libby City Of water safe to drink?
Libby City Of (PWS ID: MT0000274) has 341 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 4,892 people using Surface Water sources.
How many people does Libby City Of serve?
Libby City Of serves 4,892 people in Libby, Montana. It is a Local-owned system using Surface Water water sources with 1,957 service connections.
What type of violations does Libby City Of have?
Libby City Of has 341 total violations: 100 health-based violations (MCL exceedances or treatment failures), 221 monitoring/reporting violations, and 100 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Libby City Of water?
No. Libby City Of was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Libby City Of use?
Libby City Of 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.
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.
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.