Public water system · MT0005111
ActiveSunset Colony Unapproved
At a glance
Sunset Colony Unapproved (PWSID MT0005111) is an active community water system in Musselshell County, Montana. It reports serving 75 people through 2 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 2 violations for this system; none is health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
75
Service connections
2
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Sunset Colony Unapproved compare with other water systems in Musselshell County?
By EPA's size categories, Sunset Colony Unapproved is a very small system (500 people or fewer). Musselshell County has 7 active public water systems, and Sunset Colony Unapproved is the 5th-largest of them by population served. Its population served is well below the county average of 399 people per system, and accounts for 2.7% of the 2,795 people reported by systems filed under the county. Across Montana, the 2,378 active systems average 489 people each. Nationally, the average active community water system reports serving 6,703 people, so Sunset Colony Unapproved is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Montana has 853 active community water systems, 36% 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 Sunset Colony Unapproved?
EPA lists Sunset Colony Unapproved 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. 4 of the 7 active systems in Musselshell County (57%) are also privately owned.
Does Sunset Colony Unapproved have drinking water violations?
EPA's records list 2 violations for this system; none is health-based, and the most recent began in January 2026. The violations listed here began between December 2025 and January 2026. By type: 2 monitoring. The contaminant or rule involved most often is Revised Total Coliform Rule (2 of them). EPA lists 1 as resolved 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. 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 |
|---|---|---|---|---|
| 2026-01-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2025-12-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Archived |
All 2 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.
Sunset Colony Unapproved: frequently asked questions
Who runs Sunset Colony Unapproved?
Sunset Colony Unapproved (PWSID MT0005111) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Sunset Colony Unapproved serve?
Sunset Colony Unapproved reports serving 75 people through 2 service connections in Musselshell County, Montana.
Where does Sunset Colony Unapproved 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 Sunset Colony Unapproved have any drinking water violations?
EPA's records list 2 violations for this system; none is health-based, and the most recent began in January 2026. 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 Sunset Colony Unapproved'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. EPA's records list 2 violations for this system; none is health-based, and the most recent began in January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Sunset Colony Unapproved's water quality report?
As a community water system, Sunset Colony Unapproved must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Musselshell County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Roundup Water Department | Musselshell | 1,900 | Community | Groundwater |
| Picchionis Iga | Musselshell | 300 | Transient non-community | Purchased groundwater |
| Signal Peak Energy Bull Mountain Coal | Musselshell | 250 | Non-transient non-community | Groundwater |
| Melstone Town of | Musselshell | 170 | Community | Groundwater |
| Musselshell Community County Wsd | Musselshell | 75 | Community | Groundwater |
| Van Dykes Grocery Store - Sparkling Pure | Musselshell | 25 | Transient non-community | Purchased groundwater |
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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, “Sunset Colony Unapproved, PWSID MT0005111, Montana”, https://aquacensus.com/water-systems/montana/sunset-colony-unapproved-mt0005111 (data as of October 1, 2026).