Public water system · MT0004468
ActiveAndesite Ridge Water System
At a glance
Andesite Ridge Water System (PWSID MT0004468) is an active community water system in Madison County, Montana. It reports serving 450 people through 223 service connections. Its primary water source is purchased groundwater, and EPA lists it as privately owned. EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in July 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
450
Service connections
223
Primary source
GWP
Purchased groundwater
System type
CWS
Community water system
System record
How does Andesite Ridge Water System compare with other water systems in Madison County?
By EPA's size categories, Andesite Ridge Water System is a very small system (500 people or fewer). Madison County has 45 active public water systems. Its population served is about 41% above the county average of 320 people per system, and accounts for 3.1% of the 14,392 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 Andesite Ridge Water System 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. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. 104 Montana systems (4.4%) list purchased groundwater as their primary source.
Who owns and regulates Andesite Ridge Water System?
EPA lists Andesite Ridge Water System 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. 26 of the 45 active systems in Madison County (58%) are also privately owned.
Does Andesite Ridge Water System have drinking water violations?
EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in July 2020. The violations listed here began between April 2006 and July 2020. By type: 4 monitoring and reporting, 3 contaminant level above the legal limit, 2 public notice, recordkeeping or other and 1 required treatment not met. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 10 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 |
|---|---|---|---|---|
| 2020-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-07-01 | Required treatment not metOCCT/SOWT Study/Recommendation · code 57 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2010-11-01 | Public notice, recordkeeping or otherFailure to Notify Other PWS · code 73 | Groundwater Rulecode 0700 | No | Resolved |
| 2010-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-02-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2009-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2007-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2006-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 10 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.
Andesite Ridge Water System: frequently asked questions
Who runs Andesite Ridge Water System?
Andesite Ridge Water System (PWSID MT0004468) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Andesite Ridge Water System serve?
Andesite Ridge Water System reports serving 450 people through 223 service connections in Madison County, Montana.
Where does Andesite Ridge Water System get its water?
EPA SDWIS lists this system's primary water source as purchased groundwater. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own.
Does Andesite Ridge Water System have any drinking water violations?
EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in July 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 Andesite Ridge Water System'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 10 violations for this system; 4 are health-based, and the most recent began in July 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Andesite Ridge Water System's water quality report?
As a community water system, Andesite Ridge Water System 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 Madison County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Big Sky County Water and Sewer Dist 363 | Madison | 4,132 | Community | Groundwater |
| Virginia City Water Dept | Madison | 1,500 | Community | Groundwater |
| Ennis Town of | Madison | 1,400 | Community | Groundwater |
| Sheridan Town of | Madison | 632 | Community | Groundwater |
| Nevada City | Madison | 621 | Transient non-community | Groundwater |
| Earthquake Lake Visitor Center | Madison | 503 | 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, “Andesite Ridge Water System, PWSID MT0004468, Montana”, https://aquacensus.com/water-systems/montana/andesite-ridge-water-system-mt0004468 (data as of October 1, 2026).