Public water system · MT0003894
ActiveStillwater East Boulder
At a glance
Stillwater East Boulder (PWSID MT0003894) is an active non-transient non-community water system in Sweet Grass County, Montana. It reports serving 380 people through 6 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 3 violations for this system; none is health-based, and the most recent began in December 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
380
Service connections
6
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Stillwater East Boulder compare with other water systems in Sweet Grass County?
By EPA's size categories, Stillwater East Boulder is a very small system (500 people or fewer). Sweet Grass County has 16 active public water systems, and Stillwater East Boulder is the 5th-largest of them by population served. Its population served is about 17% below the county average of 457 people per system, and accounts for 5.2% 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 non-transient non-community water system reports serving 430 people, so Stillwater East Boulder is about 12% below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. Montana has 319 active non-transient non-community water systems, 13% 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 Stillwater East Boulder?
EPA lists Stillwater East Boulder 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 Stillwater East Boulder have drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in December 2020. The violations listed here began between October 2007 and December 2020. By type: 2 monitoring and reporting and 1 monitoring. The contaminant or rule involved most often is Lead and Copper Rule (2 of them). EPA lists 3 as resolved. 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 |
|---|---|---|---|---|
| 2020-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2018-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2007-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
All 3 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.
Stillwater East Boulder: frequently asked questions
Who runs Stillwater East Boulder?
Stillwater East Boulder (PWSID MT0003894) is a non-transient non-community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Stillwater East Boulder serve?
Stillwater East Boulder reports serving 380 people through 6 service connections in Sweet Grass County, Montana.
Where does Stillwater East Boulder 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 Stillwater East Boulder have any drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in December 2020. 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 Stillwater East Boulder'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 3 violations for this system; none is health-based, and the most recent began in December 2020. For current results, consult EPA ECHO, or the MT state drinking water program.
Where can I find Stillwater East Boulder's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Stillwater East Boulder is a non-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 |
| Big Timber Koa | Sweet Grass | 600 | 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 |
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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, “Stillwater East Boulder, PWSID MT0003894, Montana”, https://aquacensus.com/water-systems/montana/stillwater-east-boulder-mt0003894 (data as of October 1, 2026).