Public water system · MT0001783
ActiveRimrock Colony
At a glance
Rimrock Colony (PWSID MT0001783) is an active community water system in Toole County, Montana. It reports serving 124 people through 8 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 11 violations for this system; none is health-based, and the most recent began in September 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
124
Service connections
8
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Rimrock Colony compare with other water systems in Toole County?
By EPA's size categories, Rimrock Colony is a very small system (500 people or fewer). Toole County has 18 active public water systems. Its population served is about 66% below the county average of 361 people per system, and accounts for 1.9% of the 6,498 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 Rimrock Colony 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 Rimrock Colony?
EPA lists Rimrock Colony 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. 10 of the 18 active systems in Toole County (56%) are also privately owned.
Does Rimrock Colony have drinking water violations?
EPA's records list 11 violations for this system; none is health-based, and the most recent began in September 2023. The violations listed here began between June 1981 and September 2023. By type: 10 monitoring and reporting and 1 monitoring. The contaminants or rules involved are E. coli, Revised Total Coliform Rule, Total coliform bacteria (TCR) and Fluoride. EPA lists 8 as archived and 3 as resolved. 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. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2023-09-20 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2020-12-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 1992-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Cadmiumcode 1015 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Mercurycode 1035 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Seleniumcode 1045 | No | Archived |
| 1981-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Bariumcode 1010 | No | Archived |
All 11 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.
Rimrock Colony: frequently asked questions
Who runs Rimrock Colony?
Rimrock Colony (PWSID MT0001783) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Rimrock Colony serve?
Rimrock Colony reports serving 124 people through 8 service connections in Toole County, Montana.
Where does Rimrock Colony 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 Rimrock Colony have any drinking water violations?
EPA's records list 11 violations for this system; none is health-based, and the most recent began in September 2023. 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 Rimrock Colony'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 11 violations for this system; none is health-based, and the most recent began in September 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Rimrock Colony's water quality report?
As a community water system, Rimrock Colony 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 Toole County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Shelby City of | Toole | 3,970 | Community | Groundwater |
| Sunburst Town of | Toole | 459 | Community | Groundwater |
| Oilmont County Water District | Toole | 300 | Community | Groundwater |
| Ncmrwa North Shelby | Toole | 300 | Community | Purchased groundwater |
| Kevin Town of | Toole | 290 | Community | Groundwater |
| Galata County Water District | Toole | 200 | Community | 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, “Rimrock Colony, PWSID MT0001783, Montana”, https://aquacensus.com/water-systems/montana/rimrock-colony-mt0001783 (data as of October 1, 2026).