Public water system · ID4200032
ActiveMountain Home, City of
At a glance
City of Mountain Home (PWSID ID4200032) is an active community water system in Elmore County, Idaho. It reports serving 14,651 people through 5,842 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in August 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
14,651
Service connections
5,842
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Mountain Home compare with other water systems in Elmore County?
By EPA's size categories, City of Mountain Home is a large system (10,001 to 100,000 people). Elmore County has 44 active public water systems, and City of Mountain Home is the largest of them by population served. Its population served is about 24 times the county average of 607 people per system, and accounts for 55% of the 26,726 people reported by systems filed under the county. Across Idaho, the 1,961 active systems average 899 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Mountain Home is about twice 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. Idaho has 765 active community water systems, 39% of the state's 1,961 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,861 Idaho systems (95%) list groundwater as their primary source.
Who owns and regulates City of Mountain Home?
EPA lists City of Mountain Home as owned by a local government. The ID state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 3 of the 44 active systems in Elmore County (6.8%) are also owned by a local government.
Does City of Mountain Home have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in August 2025. The violations listed here began between January 2023 and August 2025. By type: 9 monitoring and reporting, 2 required treatment not met and 1 reporting. The contaminant or rule involved most often is Lead and Copper Rule Revisions (2 of them). EPA lists 7 as archived, 3 as resolved and 2 as unaddressed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-08-01 | Required treatment not metTreatment Technique, Level 1 Assessment (RTCR) · code 2A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Resolved |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Resolved |
| 2024-09-30 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Unaddressed |
| 2024-07-22 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Unaddressed |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Endothallcode 2033 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Picloramcode 2040 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Atrazinecode 2050 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzo(a)pyrenecode 2306 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,4,5-TP (Silvex)code 2110 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Archived |
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.
City of Mountain Home: frequently asked questions
Who runs City of Mountain Home?
City of Mountain Home (PWSID ID4200032) is a community water system owned by a local government. It is regulated by the ID state drinking water program.
How many people does City of Mountain Home serve?
City of Mountain Home reports serving 14,651 people through 5,842 service connections in Elmore County, Idaho.
Where does City of Mountain Home 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 City of Mountain Home have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in August 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 City of Mountain Home'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, 2 are health-based, and the most recent began in August 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the ID state drinking water program.
Where can I find City of Mountain Home's water quality report?
As a community water system, City of Mountain Home 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 Elmore County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Mountain Home Air Force Base | Elmore | 7,500 | Community | Groundwater |
| Glenns Ferry City of | Elmore | 1,282 | Community | Surface water |
| Trinity Estates Water Users Assn | Elmore | 250 | Community | Groundwater |
| Mellen Subd Water Dist | Elmore | 250 | Community | Purchased groundwater |
| Canyon Creek Mobile Home Park | Elmore | 243 | Community | Groundwater |
| Summerwind Water Users | Elmore | 192 | 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, “Mountain Home, City of, PWSID ID4200032, Idaho”, https://aquacensus.com/water-systems/idaho/mountain-home-city-of-id4200032 (data as of October 1, 2026).