Custer County, Montana — public water systems

At a glance

11 active public water systems are filed under Custer County, Montana in EPA's SDWIS records, together reporting 10,579 people served. The largest is City of Miles City, which reports serving 9,565 people. 4 are community water systems serving people where they live; the other 7 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO, refreshed quarterly.

Active systems

Population served

10.6K

Community systems

Groundwater share

54.5%

How does Custer County compare with other Montana counties?

Custer County has the 38th-most active public water systems among the 76 counties listed for active Montana systems in EPA records; among the 55 with 3 or more systems, the median has 16. Its systems report 10,579 people served in total, the 17th-largest county figure in the state and 0.9% of the statewide total. The average system here reports serving 962 people, about twice the Montana average of 489. 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 Custer County's drinking water come from?

By primary water source, Custer County's active systems draw on groundwater (6, 55%), purchased surface water (4, 36%) and surface water (1, 9.1%). Overall, 55% rely mainly on groundwater (including purchased groundwater) and 45% on surface water, compared with 89% and 11% across Montana. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, City of Miles City, draws primarily on surface water.

What kinds of water systems operate in Custer County?

Custer County's active systems break down as 4 community systems (36%), 2 non-transient non-community systems (18%) and 5 transient non-community systems (45%). 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 (55%), local government (36%) and state government (9.1%).

Water systems in Custer County

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Active public water systems in Custer County, Montana
#	Water system	County	Population served	Type	Source
1	Miles City City of	Custer	9,565	Community	Surface water
2	Custer Co Water and Sewer Dist	Custer	480	Community	Purchased surface water
3	Pine Hills Youth Correct Facil	Custer	193	Community	Purchased surface water
4	Kinsey School District 63	Custer	86	Non-transient non-community	Groundwater
5	Big Sky Camp and Rv Park	Custer	56	Transient non-community	Groundwater
6	Palisades Apartments	Custer	50	Community	Groundwater
7	Kircher School Dist 03	Custer	45	Non-transient non-community	Groundwater
8	Motel Miles	Custer	29	Transient non-community	Groundwater
9	June'S Bungalow	Custer	25	Transient non-community	Groundwater
10	Primo Refill Wal-Mart No 2608	Custer	25	Transient non-community	Purchased surface water
11	Albertsons Miles City No 2039	Custer	25	Transient non-community	Purchased surface water

Custer County water systems: frequently asked questions

How many public water systems are in Custer County, Montana?

EPA's SDWIS records file 11 active public water systems under Custer County, Montana: 4 community systems (36%), 2 non-transient non-community systems (18%) and 5 transient non-community systems (45%).

Who supplies drinking water in Custer County, MT?

The largest community water systems filed under Custer County are City of Miles City (9,565 people served), Custer Co Water and Sewer Dist (480 people served) and Pine Hills Youth Correct Facil (193 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 Custer County's drinking water come from groundwater or surface water?

Of the 11 active public water systems in Custer County, 55% draw mainly on groundwater and 45% on surface water, counting purchased supplies. The largest system, City of Miles City, uses surface water.

Where can I find a water quality report for Custer 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. 4 community systems are filed under Custer 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 Custer 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 Montana 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 Custer County, Montana”, https://aquacensus.com/water-systems/montana/custer (data as of October 1, 2026).