Public water system · MT0001682
ActiveBig Timber Koa
At a glance
Big Timber Koa (PWSID MT0001682) is an active transient non-community water system in Sweet Grass County, Montana. It reports serving 600 people through 57 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
600
Service connections
57
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Big Timber Koa compare with other water systems in Sweet Grass County?
By EPA's size categories, Big Timber Koa is a small system (501 to 3,300 people). Sweet Grass County has 16 active public water systems, and Big Timber Koa is the 4th-largest of them by population served. Its population served is about 31% above the county average of 457 people per system, and accounts for 8.2% of the 7,304 people reported by systems filed under the county. Across Montana, the 2,378 active systems average 489 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Big Timber Koa is about 4.2 times that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. Montana has 1,206 active transient non-community water systems, 51% of the state's 2,378 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,994 Montana systems (84%) list groundwater as their primary source.
Who owns and regulates Big Timber Koa?
EPA lists Big Timber Koa as privately owned. The MT state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 13 of the 16 active systems in Sweet Grass County (81%) are also privately owned.
Does Big Timber Koa have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 2025. The violations listed here began between September 2006 and October 2025. By type: 5 monitoring and reporting, 3 required treatment not met, 3 monitoring and 1 reporting. The contaminant or rule involved most often is Revised Total Coliform Rule (7 of them). EPA lists 10 as resolved, 1 as unaddressed and 1 as archived. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-10-01 | Required treatment not metTreatment Technique Startup Procedures (RTCR) · code 2D | Revised Total Coliform Rulecode 8000 | Yes | Unaddressed |
| 2025-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Archived |
| 2022-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-04-02 | Required treatment not metTreatment Technique Startup Procedures (RTCR) · code 2D | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2021-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2020-06-02 | ReportingReport Startup Procedures Cert Form (RTCR) · code 4C | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2016-06-02 | Required treatment not metTreatment Technique Startup Procedures (RTCR) · code 2D | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2008-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2008-05-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2006-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Big Timber Koa: frequently asked questions
Who runs Big Timber Koa?
Big Timber Koa (PWSID MT0001682) is a transient non-community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Big Timber Koa serve?
Big Timber Koa reports serving 600 people through 57 service connections in Sweet Grass County, Montana.
Where does Big Timber Koa get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Big Timber Koa have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Big Timber Koa's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 2025. For current results, consult EPA ECHO, or the MT state drinking water program.
Where can I find Big Timber Koa's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Big Timber Koa is a transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Sweet Grass County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Greycliff Rest Area Eastbound | Sweet Grass | 2,500 | Transient non-community | Groundwater |
| Big Timber City of | Sweet Grass | 1,650 | Community | Surface water |
| Greycliff Rest Area Westbound | Sweet Grass | 1,000 | Transient non-community | Groundwater |
| Stillwater East Boulder | Sweet Grass | 380 | Non-transient non-community | Groundwater |
| Town Pump 1033 Big Timber # 2 | Sweet Grass | 318 | Transient non-community | Groundwater |
| Clydehurst Christian Ranch | Sweet Grass | 175 | Transient non-community | Groundwater |
Related pages
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Big Timber Koa, PWSID MT0001682, Montana”, https://aquacensus.com/water-systems/montana/big-timber-koa-mt0001682 (data as of October 1, 2026).