Big Horn County, Montana — public water systems

23 active public water systems serve Big Horn County, reporting 10.3K people served.

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

Active systems

Population served

10.3K

Community systems

Groundwater share

65.2%

Water systems in Big Horn County

Active public water systems in Big Horn County, Montana
#	Water system	County	Population served	Type	Source
1	Hardin City of	Big Horn	3,500	Community	Surface water
2	Little Bighorn Battlefield Nm	Big Horn	2,020	Non-transient non-community	Groundwater
3	Hardin Eastbound Rest Area	Big Horn	877	Transient non-community	Groundwater
4	Hardin Westbound Rest Area	Big Horn	715	Transient non-community	Groundwater
5	Lodge Grass Town of	Big Horn	480	Community	Groundwater
6	Fort Smith Water and Sewer District	Big Horn	450	Community	Groundwater
7	Tongue River Campers Point	Big Horn	305	Transient non-community	Groundwater
8	Tongue River Pee Wee Point	Big Horn	300	Transient non-community	Groundwater
9	Chief Plenty Coups Museum	Big Horn	262	Transient non-community	Groundwater
10	Big Horn Co Historical Museum	Big Horn	206	Transient non-community	Purchased surface water
11	Spring Creek Mine	Big Horn	200	Non-transient non-community	Purchased surface water
12	Spring Creek Coal Domestic	Big Horn	200	Non-transient non-community	Groundwater
13	St Charles School	Big Horn	152	Non-transient non-community	Groundwater
14	Yellowtail Dam Gc System	Big Horn	125	Community	Groundwater
15	7th Ranch Rv Camp	Big Horn	102	Transient non-community	Groundwater
16	Hardin Koa Cistern	Big Horn	100	Transient non-community	Purchased surface water
17	Cottonwood Camp Fort Smith	Big Horn	85	Transient non-community	Groundwater
18	Absaloka Mine	Big Horn	80	Non-transient non-community	Purchased surface water
19	Wegner Water Service Hauler	Big Horn	50	Community	Purchased surface water
20	Yellowtail Dam Powerplant and Visitor Ce	Big Horn	48	Transient non-community	Surface water
21	East Decker Coal Mine	Big Horn	28	Non-transient non-community	Groundwater
22	Kirby Saloon	Big Horn	25	Transient non-community	Groundwater
23	Reese and Ray Iga Hardin	Big Horn	25	Transient non-community	Purchased surface water