Public water system · MT0003801
ActiveMission Mountain Lake Co W and S Dist
At a glance
Mission Mountain Lake Co W and S Dist (PWSID MT0003801) is an active community water system in Lake County, Montana. It reports serving 118 people through 39 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
118
Service connections
39
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Mission Mountain Lake Co W and S Dist compare with other water systems in Lake County?
By EPA's size categories, Mission Mountain Lake Co W and S Dist is a very small system (500 people or fewer). Lake County has 90 active public water systems. Its population served is about half of the county average of 220 people per system, and accounts for 0.6% of the 19,829 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 Mission Mountain Lake Co W and S Dist 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 Mission Mountain Lake Co W and S Dist?
EPA lists Mission Mountain Lake Co W and S Dist 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. 71 of the 90 active systems in Lake County (79%) are also privately owned.
Does Mission Mountain Lake Co W and S Dist have drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2021. The violations listed here began between January 1996 and October 2021. By type: 7 monitoring and reporting, 1 monitoring and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 9 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 |
|---|---|---|---|---|
| 2021-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 1999-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1997-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1997-06-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Thalliumcode 1085 | No | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Berylliumcode 1075 | No | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nickelcode 1036 | No | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Antimonycode 1074 | No | Resolved |
All 9 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.
Mission Mountain Lake Co W and S Dist: frequently asked questions
Who runs Mission Mountain Lake Co W and S Dist?
Mission Mountain Lake Co W and S Dist (PWSID MT0003801) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Mission Mountain Lake Co W and S Dist serve?
Mission Mountain Lake Co W and S Dist reports serving 118 people through 39 service connections in Lake County, Montana.
Where does Mission Mountain Lake Co W and S Dist 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 Mission Mountain Lake Co W and S Dist have any drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2021. 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 Mission Mountain Lake Co W and S Dist'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 9 violations for this system; 1 is health-based, and the most recent began in October 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Mission Mountain Lake Co W and S Dist's water quality report?
As a community water system, Mission Mountain Lake Co W and S Dist 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 Lake County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Polson City of | Lake | 5,300 | Community | Groundwater |
| Ronan City of | Lake | 2,483 | Community | Surface water |
| Pablo Lake County Water and Sewer Dist | Lake | 2,175 | Community | Groundwater |
| St Ignatius Town of | Lake | 700 | Community | Groundwater |
| Woods Bay Water and Sewer District | Lake | 685 | Community | Groundwater |
| Wilson Foods | Lake | 600 | 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, “Mission Mountain Lake Co W and S Dist, PWSID MT0003801, Montana”, https://aquacensus.com/water-systems/montana/mission-mountain-lake-co-w-and-s-dist-mt0003801 (data as of October 1, 2026).