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Community Water System · PWS MT0000525

Great Falls City Of

Great Falls, Montana 59403 - drinking water served from surface water sources to 60,000 people, tracked in EPA SDWIS and UCMR5.

60,000
People served
26
EPA violations
18
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 26 drinking-water violations at Great Falls City Of, 69% of them health-based - below the Montana per-system average.

26
Total EPA violations on record
69%
Health-based (MCL / treatment failure)
60,000
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Great Falls City Of

Great Falls City Of is a local-owned community water system that delivers drinking water to 60,000 residents in Great Falls, Montana (Cascade County) through 22,477 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 26 total violations for this system , of which 18 (69%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 7 monitoring and reporting violations are on file. The most recent violation on record dates to 2019.

The most frequently cited contaminant at this system is Total Haloacetic Acids (HAA5), recorded in 16 violations (MCL, 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%).

Great Falls City Of's 26 violations sit below 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
60,000
Total Violations
26
Health-Based Violations
18
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
22,477
County
Cascade
School/Daycare
No
MCL Violations
16
Monitoring Violations
7
Treatment Tech Violations
2

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Total Haloacetic Acids (HAA5) MCL 16 2019
Total Haloacetic Acids (HAA5) MR 3 2006
TTHM MR 3 2006
Surface Water Treatment Rule TT 2 1997
Asbestos MR 1 2002

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 116 samples detected PFAS.

Contaminant Date Result MRL Status
PFPeA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 9/18/2023 <2.00 ppt 2.00 ppt Not Detected
ADONA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 9/18/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 9/18/2023 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 9/18/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
PFUnA 9/18/2023 <2.00 ppt 2.00 ppt Not Detected
PFMPA 9/18/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 9/18/2023 <4.00 ppt 4.00 ppt Not Detected
PFMBA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
PFEESA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 9/18/2023 <5.00 ppt 5.00 ppt Not Detected
PFDoA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 9/18/2023 <20.00 ppt 20.00 ppt Not Detected
PFOA 9/18/2023 <4.00 ppt 4.00 ppt Not Detected
11Cl-PF3OUdS 9/18/2023 <5.00 ppt 5.00 ppt Not Detected
PFNA 9/18/2023 <4.00 ppt 4.00 ppt Not Detected
PFHxS 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
NMeFOSAA 9/18/2023 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 9/18/2023 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 9/18/2023 <7.00 ppt 7.00 ppt Not Detected
PFTA 9/18/2023 <8.00 ppt 8.00 ppt Not Detected
PFDA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeS 9/18/2023 <4.00 ppt 4.00 ppt Not Detected
PFHpS 9/18/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 6/8/2023 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 6/8/2023 <5.00 ppt 5.00 ppt Not Detected
PFUnA 6/8/2023 <2.00 ppt 2.00 ppt Not Detected
PFHxA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFDA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFOA 6/8/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 6/8/2023 <4.00 ppt 4.00 ppt Not Detected
ADONA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxS 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFNA 6/8/2023 <4.00 ppt 4.00 ppt Not Detected
HFPO-DA 6/8/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 6/8/2023 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 6/8/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 6/8/2023 <5.00 ppt 5.00 ppt Not Detected
PFPeA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
PFEESA 6/8/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 6/8/2023 <20.00 ppt 20.00 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 Great Falls 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 MT0000525 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
2019 Total Haloacetic Acids (HAA5) MCL 16 SDWIS / MT0000525 / 2456
2006 Total Haloacetic Acids (HAA5) MR 3 SDWIS / MT0000525 / 2456
2006 TTHM MR 3 SDWIS / MT0000525 / 2950
2002 Asbestos MR 1 SDWIS / MT0000525 / 1094
1997 Surface Water Treatment Rule TT 2 SDWIS / MT0000525 / 0200

How Great Falls City Of Compares

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

Metric Great Falls City Of Montana avg Federal benchmark
Total violations 26 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 18 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 60,000 492 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 Great Falls City Of water safe to drink? ▼
Great Falls City Of (PWS ID: MT0000525) has 26 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 60,000 people using Surface Water sources.
How many people does Great Falls City Of serve? ▼
Great Falls City Of serves 60,000 people in Great Falls, Montana. It is a Local-owned system using Surface Water water sources with 22,477 service connections.
What type of violations does Great Falls City Of have? ▼
Great Falls City Of has 26 total violations: 18 health-based violations (MCL exceedances or treatment failures), 7 monitoring/reporting violations, and 2 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Great Falls City Of water? ▼
No. Great Falls City Of was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Great Falls City Of use? ▼
Great Falls 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.

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

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.