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Elmore County, Idaho — public water systems

At a glance

44 active public water systems are filed under Elmore County, Idaho in EPA's SDWIS records, together reporting 26,726 people served. The largest is City of Mountain Home, which reports serving 14,651 people. 24 are community water systems serving people where they live; the other 20 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.

Dataset updated . Source: EPA SDWIS/ECHO, refreshed quarterly.

Active systems

44

Population served

26.7K

Community systems

24

Groundwater share

95.5%

How does Elmore County compare with other Idaho counties?

Elmore County has the 16th-most active public water systems among the 64 counties listed for active Idaho systems in EPA records; among the 47 with 3 or more systems, the median has 27. Its systems report 26,726 people served in total, the 12th-largest county figure in the state and 1.5% of the statewide total. The average system here reports serving 607 people, about 32% below the Idaho average of 899. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.

Where does Elmore County's drinking water come from?

By primary water source, Elmore County's active systems draw on groundwater (40, 91%), surface water (2, 4.5%), groundwater under influence of surface water (1, 2.3%) and purchased groundwater (1, 2.3%). Overall, 95% rely mainly on groundwater (including purchased groundwater) and 4.5% on surface water, compared with 96% and 4.1% across Idaho. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, City of Mountain Home, draws primarily on groundwater.

What kinds of water systems operate in Elmore County?

Elmore County's active systems break down as 24 community systems (55%), 2 non-transient non-community systems (4.5%) and 18 transient non-community systems (41%). 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. 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. A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. EPA lists their owner types as private (89%), local government (6.8%) and federal government (4.5%).

Water systems in Elmore County

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Active public water systems in Elmore County, Idaho
#Water systemCountyPopulation servedTypeSource
1Mountain Home, City ofElmore14,651CommunityGroundwater
2Mountain Home Air Force BaseElmore7,500CommunityGroundwater
3Glenns Ferry City ofElmore1,282CommunitySurface water
4Trinity Estates Water Users AssnElmore250CommunityGroundwater
5Mellen Subd Water DistElmore250CommunityPurchased groundwater
6Canyon Creek Mobile Home ParkElmore243CommunityGroundwater
7Summerwind Water UsersElmore192CommunityGroundwater
8Sawtooth Estates Water UsersElmore175CommunityGroundwater
9LDS Church Mountain Home AirbaseElmore150Transient non-communityGroundwater
10Blue Sage SubdivisionElmore112CommunityGroundwater
11Elk Valley ResortElmore100Transient non-communityGroundwater
12Simplot Livestock Company GrandviewElmore100CommunityGroundwater
13Hamilton PlaceElmore97CommunityGroundwater
14Atlanta Water AssnElmore91CommunitySurface water
15Splendid Acres Water AssnElmore91CommunityGroundwater
16Trinity View ResortElmore90Transient non-communityGroundwater
17King Hill Domestic Water and SewerElmore87CommunityGroundwater
18Town and Country Water Users AssnElmore86CommunityGroundwater
19Pleasant Acres Mobile Home ParkElmore85CommunityGroundwater
20New Horizons Water Inc.Elmore85CommunityGroundwater
21Mountain Home Migrant Head StartElmore78Non-transient non-communityGroundwater
22TlkElmore75Non-transient non-communityGroundwater
23Oakleaf SubdivisionElmore71CommunityGroundwater
24Mountain SageElmore65CommunityGroundwater
25Hammett Haven ApartmentsElmore64CommunityGroundwater
26Featherville Townsite Water CorpElmore60CommunityGroundwater under influence of surface water
27Danskin Properties Association Inc.Elmore52CommunityGroundwater
28Desert Winds ChevronElmore50Transient non-communityGroundwater
29Key Mart CornerElmore50Transient non-communityGroundwater
30Camas Estates Water UsersElmore50CommunityGroundwater
31Riverview Subd Water AssnElmore45Transient non-communityGroundwater
32Paradise Homeowners Assn Inc.Elmore43Transient non-communityGroundwater
33Silver Sage Real Property Owners AssnElmore30CommunityGroundwater
34ShiokElmore26Transient non-communityGroundwater
35Pine ResortElmore26Transient non-communityGroundwater
36Nitz' Pine StoreElmore25Transient non-communityGroundwater
37Y-Stop General StoreElmore25Transient non-communityGroundwater
38Mountain Home Afb Cj Strike Dam Rec CtrElmore25Transient non-communityGroundwater
39South Fork Senior CenterElmore25Transient non-communityGroundwater
40Mcguires SubdElmore25Transient non-communityGroundwater
41Fall Creek Recreational RetreatElmore25Transient non-communityGroundwater
42Bakers Acres Association Inc.Elmore25Transient non-communityGroundwater
43Cj Strike North ParkElmore25Transient non-communityGroundwater
44Ballantyne Camp Subd 1Elmore24Transient non-communityGroundwater

Elmore County water systems: frequently asked questions

How many public water systems are in Elmore County, Idaho?

EPA's SDWIS records file 44 active public water systems under Elmore County, Idaho: 24 community systems (55%), 2 non-transient non-community systems (4.5%) and 18 transient non-community systems (41%).

Who supplies drinking water in Elmore County, ID?

The largest community water systems filed under Elmore County are City of Mountain Home (14,651 people served), Mountain Home Air Force Base (7,500 people served) and City of Glenns Ferry (1,282 people served). Which system serves a particular address depends on its service area, which EPA's SDWIS records do not include; a water bill or the local utility can confirm it.

Does Elmore County's drinking water come from groundwater or surface water?

Of the 44 active public water systems in Elmore County, 95% draw mainly on groundwater and 4.5% on surface water, counting purchased supplies. The largest system, City of Mountain Home, uses groundwater.

Where can I find a water quality report for Elmore County?

Each community water system must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1, covering the previous calendar year. 24 community systems are filed under Elmore County, so the report to look for is the one from the system that supplies your address.

How can I check violations for a water system in Elmore County?

Open the system's profile from the list on this page. Each profile shows the most recent Safe Drinking Water Act violations in EPA's records, with plain-English labels and whether each one is resolved. For current compliance status, EPA ECHO is the primary source.

More Idaho water systems

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, “Public water systems in Elmore County, Idaho”, https://aquacensus.com/water-systems/idaho/elmore (data as of October 1, 2026).