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Community Water System · PWS MT0000580

Two Buttes Water Users Assn

Fort Shaw, Montana 59443 - drinking water served from groundwater sources to 525 people, tracked in EPA SDWIS and UCMR5.

525
People served
119
EPA violations
8
Health-based
Untested
UCMR5 result

The verdict

EPA records 119 drinking-water violations at Two Buttes Water Users Assn, 7% of them health-based - below the Montana per-system average.

119
Total EPA violations on record
7%
Health-based (MCL / treatment failure)
525
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Two Buttes Water Users Assn

Two Buttes Water Users Assn is a private-owned community water system that delivers drinking water to 525 residents in Fort Shaw, Montana (Cascade County) through 126 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 119 total violations for this system , of which 8 (7%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 75 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 Chlorine, recorded in 30 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%).

Two Buttes Water Users Assn's 119 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
525
Total Violations
119
Health-Based Violations
8
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
126
County
Cascade
School/Daycare
No
MCL Violations
8
Monitoring Violations
75
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Chlorine MR 30 2017
Consumer Confidence Rule Other 24 2017
Coliform (TCR) MR 17 2012
Lead and Copper Rule MR 11 2014
Coliform (TCR) MCL 5 2002
Nitrate-Nitrite MR 4 2011
Asbestos MR 3 2011
E. COLI MR 3 2017
Combined Radium (-226 and -228) MCL 3 2002
Revised Total Coliform Rule Other 3 2016
TTHM MR 3 2019
Total Haloacetic Acids (HAA5) MR 3 2019
Nitrate MR 1 1993

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 Two Buttes Water Users Assn.

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 MT0000580 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 TTHM MR 3 SDWIS / MT0000580 / 2950
2019 Total Haloacetic Acids (HAA5) MR 3 SDWIS / MT0000580 / 2456
2017 Chlorine MR 30 SDWIS / MT0000580 / 0999
2017 Consumer Confidence Rule Other 24 SDWIS / MT0000580 / 7000
2017 E. COLI MR 3 SDWIS / MT0000580 / 3014
2016 Revised Total Coliform Rule Other 3 SDWIS / MT0000580 / 8000
2014 Lead and Copper Rule MR 11 SDWIS / MT0000580 / 5000
2012 Coliform (TCR) MR 17 SDWIS / MT0000580 / 3100
2011 Nitrate-Nitrite MR 4 SDWIS / MT0000580 / 1038
2011 Asbestos MR 3 SDWIS / MT0000580 / 1094
2002 Coliform (TCR) MCL 5 SDWIS / MT0000580 / 3100
2002 Combined Radium (-226 and -228) MCL 3 SDWIS / MT0000580 / 4010
1993 Nitrate MR 1 SDWIS / MT0000580 / 1040

How Two Buttes Water Users Assn Compares

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

Metric Two Buttes Water Users Assn Montana avg Federal benchmark
Total violations 119 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 8 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 525 492 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 Two Buttes Water Users Assn water safe to drink? ▼
Two Buttes Water Users Assn (PWS ID: MT0000580) has 119 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 525 people using Groundwater sources.
How many people does Two Buttes Water Users Assn serve? ▼
Two Buttes Water Users Assn serves 525 people in Fort Shaw, Montana. It is a Private-owned system using Groundwater water sources with 126 service connections.
What type of violations does Two Buttes Water Users Assn have? ▼
Two Buttes Water Users Assn has 119 total violations: 8 health-based violations (MCL exceedances or treatment failures), 75 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Two Buttes Water Users Assn water? ▼
No PFAS testing data is available for Two Buttes Water Users Assn under the EPA's UCMR5 monitoring program.
What water source does Two Buttes Water Users Assn use? ▼
Two Buttes Water Users Assn uses Groundwater 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.