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Community Water System · PWS MT0000180

Colstrip City Of

Colstrip, Montana 59323 - drinking water served from surface water sources to 2,350 people, tracked in EPA SDWIS and UCMR5.

2,350
People served
133
EPA violations
7
Health-based
Untested
UCMR5 result

The verdict

EPA records 133 drinking-water violations at Colstrip City Of, 5% of them health-based - above the Montana per-system average.

133
Total EPA violations on record
5%
Health-based (MCL / treatment failure)
2,350
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Colstrip City Of

Colstrip City Of is a local-owned community water system that delivers drinking water to 2,350 residents in Colstrip, Montana (Rosebud County) through 913 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 133 total violations for this system , of which 7 (5%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 117 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is CARBON, TOTAL, recorded in 18 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

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%).

Colstrip City Of's 133 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
2,350
Total Violations
133
Health-Based Violations
7
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
913
County
Rosebud
School/Daycare
No
MCL Violations
3
Monitoring Violations
117
Treatment Tech Violations
4

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
CARBON, TOTAL MR 18 2004
Coliform (TCR) MR 16 2008
Surface Water Treatment Rule MR 9 2024
Arsenic MR 6 1999
Antimony, Total MR 5 2003
Selenium MR 5 2003
Mercury MR 5 2003
Chromium MR 5 2003
Cadmium MR 5 2003
Barium MR 5 2003
Thallium, Total MR 5 2003
Beryllium, Total MR 5 2003
Nickel MR 5 2003
Surface Water Treatment Rule TT 4 2024
Lead and Copper Rule MR 3 2001
Fluoride MR 3 2003
Revised Total Coliform Rule MON 3 2022
TTHM MCL 3 2024
Nitrate-Nitrite MR 3 2000
Asbestos MR 3 2011
Total Haloacetic Acids (HAA5) MR 3 2023
TTHM MR 3 2023
Nitrate MR 2 1996

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 Colstrip 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 MT0000180 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
2024 Surface Water Treatment Rule MR 9 SDWIS / MT0000180 / 0200
2024 Surface Water Treatment Rule TT 4 SDWIS / MT0000180 / 0200
2024 TTHM MCL 3 SDWIS / MT0000180 / 2950
2023 Total Haloacetic Acids (HAA5) MR 3 SDWIS / MT0000180 / 2456
2023 TTHM MR 3 SDWIS / MT0000180 / 2950
2022 Revised Total Coliform Rule MON 3 SDWIS / MT0000180 / 8000
2011 Asbestos MR 3 SDWIS / MT0000180 / 1094
2008 Coliform (TCR) MR 16 SDWIS / MT0000180 / 3100
2004 CARBON, TOTAL MR 18 SDWIS / MT0000180 / 2920
2003 Antimony, Total MR 5 SDWIS / MT0000180 / 1074
2003 Selenium MR 5 SDWIS / MT0000180 / 1045
2003 Mercury MR 5 SDWIS / MT0000180 / 1035
2003 Chromium MR 5 SDWIS / MT0000180 / 1020
2003 Cadmium MR 5 SDWIS / MT0000180 / 1015
2003 Barium MR 5 SDWIS / MT0000180 / 1010

How Colstrip City Of Compares

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

Metric Colstrip City Of Montana avg Federal benchmark
Total violations 133 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 7 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 2,350 492 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 Colstrip City Of water safe to drink? ▼
Colstrip City Of (PWS ID: MT0000180) has 133 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 2,350 people using Surface Water sources.
How many people does Colstrip City Of serve? ▼
Colstrip City Of serves 2,350 people in Colstrip, Montana. It is a Local-owned system using Surface Water water sources with 913 service connections.
What type of violations does Colstrip City Of have? ▼
Colstrip City Of has 133 total violations: 7 health-based violations (MCL exceedances or treatment failures), 117 monitoring/reporting violations, and 4 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Colstrip City Of water? ▼
No PFAS testing data is available for Colstrip City Of under the EPA's UCMR5 monitoring program.
What water source does Colstrip City Of use? ▼
Colstrip 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. 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.