Public water system · MT0003587
ActiveStillwater Mining Company
At a glance
Stillwater Mining Company (PWSID MT0003587) is an active non-transient non-community water system in Stillwater County, Montana. It reports serving 630 people through 8 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, one is health-based, and the most recent began in July 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
630
Service connections
8
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Stillwater Mining Company compare with other water systems in Stillwater County?
By EPA's size categories, Stillwater Mining Company is a small system (501 to 3,300 people). Stillwater County has 30 active public water systems, and Stillwater Mining Company is the 6th-largest of them by population served. Its population served is about 126% above the county average of 278 people per system, and accounts for 7.5% of the 8,352 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 Mining Company is about 47% above 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 Mining Company?
EPA lists Stillwater Mining Company 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. 21 of the 30 active systems in Stillwater County (70%) are also privately owned.
Does Stillwater Mining Company have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2023. The violations listed here began between January 2005 and July 2023. By type: 10 monitoring and reporting, 1 monitoring and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Nitrate-Nitrite (4 of them). EPA lists 12 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 |
|---|---|---|---|---|
| 2023-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2015-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2014-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2012-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2007-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | 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.
Stillwater Mining Company: frequently asked questions
Who runs Stillwater Mining Company?
Stillwater Mining Company (PWSID MT0003587) 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 Mining Company serve?
Stillwater Mining Company reports serving 630 people through 8 service connections in Stillwater County, Montana.
Where does Stillwater Mining Company 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 Mining Company have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 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 Stillwater Mining Company'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, one is health-based, and the most recent began in July 2023. For current results, consult EPA ECHO, or the MT state drinking water program.
Where can I find Stillwater Mining Company's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Stillwater Mining Company 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 Stillwater County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Columbus Town of | Stillwater | 1,900 | Community | Groundwater |
| Cenex Zip Trip Num 50 | Stillwater | 1,500 | Transient non-community | Groundwater |
| Absarokee Water and Sewer Dist | Stillwater | 1,100 | Community | Groundwater |
| Columbus Rest Area Eastbound | Stillwater | 800 | Transient non-community | Groundwater |
| Columbus Rest Area Westbound | Stillwater | 800 | Transient non-community | Groundwater |
| Park City School K 12 | Stillwater | 300 | Non-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 Mining Company, PWSID MT0003587, Montana”, https://aquacensus.com/water-systems/montana/stillwater-mining-company-mt0003587 (data as of October 1, 2026).