Public water system · MT0004605
ActiveStone Ridge Water Company
At a glance
Stone Ridge Water Company (PWSID MT0004605) is an active community water system in Lake County, Montana. It reports serving 50 people through 31 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 May 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
50
Service connections
31
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Stone Ridge Water Company compare with other water systems in Lake County?
By EPA's size categories, Stone Ridge Water Company is a very small system (500 people or fewer). Lake County has 90 active public water systems. Its population served is well below the county average of 220 people per system, and accounts for 0.3% 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 Stone Ridge Water Company 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 Stone Ridge Water Company?
EPA lists Stone Ridge Water 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. 71 of the 90 active systems in Lake County (79%) are also privately owned.
Does Stone Ridge Water Company have drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in May 2025. The violations listed here began between April 2021 and May 2025. By type: 2 monitoring and reporting and 1 monitoring. The contaminants or rules involved are Revised Total Coliform Rule, Gross alpha (excluding radon and uranium) and Combined Radium (-226 and -228). 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 |
|---|---|---|---|---|
| 2025-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2021-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 2021-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | 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.
Stone Ridge Water Company: frequently asked questions
Who runs Stone Ridge Water Company?
Stone Ridge Water Company (PWSID MT0004605) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Stone Ridge Water Company serve?
Stone Ridge Water Company reports serving 50 people through 31 service connections in Lake County, Montana.
Where does Stone Ridge Water 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 Stone Ridge Water Company have any drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in May 2025. 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 Stone Ridge Water 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. EPA's records list 3 violations for this system; none is health-based, and the most recent began in May 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Stone Ridge Water Company's water quality report?
As a community water system, Stone Ridge Water Company 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, “Stone Ridge Water Company, PWSID MT0004605, Montana”, https://aquacensus.com/water-systems/montana/stone-ridge-water-company-mt0004605 (data as of October 1, 2026).