PlainWater
States → Montana

Community Water System · PWS MT0003978

Twin Hills Colony Inc

Carter, Montana 59420 - drinking water served from surface water sources to 78 people, tracked in EPA SDWIS and UCMR5.

78
People served
101
EPA violations
34
Health-based
Untested
UCMR5 result

The verdict

EPA records 101 drinking-water violations at Twin Hills Colony Inc, 34% of them health-based - below the Montana per-system average.

101
Total EPA violations on record
34%
Health-based (MCL / treatment failure)
78
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Twin Hills Colony Inc

Twin Hills Colony Inc is a private-owned community water system that delivers drinking water to 78 residents in Carter, Montana (Chouteau County) through 19 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 101 total violations for this system , of which 34 (34%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 65 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 Total Haloacetic Acids (HAA5), recorded in 18 violations (MCL, health-based). 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, 5 of 45 UCMR5-tested systems have reported PFAS detections (11.1%).

Twin Hills Colony Inc's 101 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
78
Total Violations
101
Health-Based Violations
34
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Private
Connections
19
County
Chouteau
School/Daycare
No
MCL Violations
34
Monitoring Violations
65
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Total Haloacetic Acids (HAA5) MCL 18 2020
TTHM MR 16 2022
Total Haloacetic Acids (HAA5) MR 16 2022
TTHM MCL 16 2020
Lead and Copper Rule MR 15 2024
Coliform (TCR) MR 9 2014
Surface Water Treatment Rule MR 6 2024
Revised Total Coliform Rule MON 3 2024
Consumer Confidence Rule Other 2 2019

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 Twin Hills Colony Inc.

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 MT0003978 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 Lead and Copper Rule MR 15 SDWIS / MT0003978 / 5000
2024 Surface Water Treatment Rule MR 6 SDWIS / MT0003978 / 0200
2024 Revised Total Coliform Rule MON 3 SDWIS / MT0003978 / 8000
2022 TTHM MR 16 SDWIS / MT0003978 / 2950
2022 Total Haloacetic Acids (HAA5) MR 16 SDWIS / MT0003978 / 2456
2020 Total Haloacetic Acids (HAA5) MCL 18 SDWIS / MT0003978 / 2456
2020 TTHM MCL 16 SDWIS / MT0003978 / 2950
2019 Consumer Confidence Rule Other 2 SDWIS / MT0003978 / 7000
2014 Coliform (TCR) MR 9 SDWIS / MT0003978 / 3100

How Twin Hills Colony Inc Compares

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

Metric Twin Hills Colony Inc Montana avg Federal benchmark
Total violations 101 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 34 11.5 Indicates a contaminant exceeded a federal MCL
PFAS detection None 11.1% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 78 492 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 Twin Hills Colony Inc water safe to drink? ▼
Twin Hills Colony Inc (PWS ID: MT0003978) has 101 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 78 people using Surface Water sources.
How many people does Twin Hills Colony Inc serve? ▼
Twin Hills Colony Inc serves 78 people in Carter, Montana. It is a Private-owned system using Surface Water water sources with 19 service connections.
What type of violations does Twin Hills Colony Inc have? ▼
Twin Hills Colony Inc has 101 total violations: 34 health-based violations (MCL exceedances or treatment failures), 65 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Twin Hills Colony Inc water? ▼
No PFAS testing data is available for Twin Hills Colony Inc under the EPA's UCMR5 monitoring program.
What water source does Twin Hills Colony Inc use? ▼
Twin Hills Colony Inc 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.