How many public water systems are in Wyoming?

Wyoming has 776 active public water systems in EPA SDWIS records, including 332 community water systems. Together they report serving 649.9K people.

What is the largest water system in Wyoming?

Cheyenne Board of Public Utilities is the largest active public water system in Wyoming, serving a reported 64,165 people.

Does Wyoming rely more on groundwater or surface water?

83.2% of Wyoming's active public water systems draw primarily on groundwater and 16.8% on surface water (including purchased supplies).

Wyoming public water systems

776 active systems regulated under the Safe Drinking Water Act, serving a reported 649.9K people across 32 counties.

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

Active systems

776

Population served

649.9K

Community systems

332

Groundwater share

83.2%

System types in Wyoming

332

Community water system

Non-transient non-community water system

354

Transient non-community water system

Largest water systems in Wyoming

The largest active public water systems in Wyoming by population served
#	Water system	County	Population served	Type	Source
1	Cheyenne Board of Public Utilities	Laramie	64,165	Community	Surface water
2	Casper, City of	Natrona	59,000	Community	Purchased surface water
3	Laramie, City of	Albany	32,395	Community	Surface water
4	Gillette, City of	Campbell	32,222	Community	Groundwater
5	Jackson, Town of	Teton	24,760	Community	Groundwater
6	Rock Springs, City of	Sweetwater	24,000	Community	Purchased surface water
7	Sheridan, City of	Sheridan	22,700	Community	Surface water
8	Evanston, City of	Uinta	12,000	Community	Surface water
9	Green River, City of	Sweetwater	10,500	Community	Purchased surface water
10	Riverton, City of	Fremont	10,330	Community	Surface water
11	Cody, City of	Park	10,224	Community	Purchased surface water
12	South Cheyenne Water & Sewer District	Laramie	10,000	Community	Purchased surface water
13	Rawlins Water Supply, City of	Carbon	9,006	Community	Surface water
14	Ynp-Old Faithful	Teton	7,675	Community	Surface water
15	Lander, City of	Fremont	7,615	Community	Surface water
16	Northwest Rural Water District	Park	7,330	Community	Purchased surface water
17	Torrington Municipal Water Dept, City of	Goshen	6,847	Community	Groundwater
18	Douglas, City of	Converse	6,400	Community	Surface water
19	Powell, City of	Park	6,310	Community	Purchased surface water
20	Ynp - Lake Village	Teton	5,925	Community	Groundwater
21	Usaf F.E. Warren Afb	Laramie	5,500	Community	Purchased surface water
22	Worland Utilities Commission	Washakie	5,487	Community	Groundwater
23	Gtnp-Colter Bay Village	Teton	4,514	Community	Groundwater
24	Buffalo, City of	Johnson	4,419	Community	Surface water
25	Ynp-Canyon Village	Park	4,300	Non-transient non-community	Surface water

By county

Teton113 systems Campbell68 systems Fremont60 systems Laramie50 systems Park49 systems Natrona48 systems Sweetwater45 systems Lincoln44 systems Platte28 systems Big Horn28 systems Crook27 systems Sublette27 systems Carbon26 systems Albany24 systems Sheridan21 systems Converse19 systems Goshen17 systems Johnson13 systems Washakie13 systems Weston12 systems Uinta12 systems Hot Springs8 systems Niobrara5 systems

Brazoria2 systems

Butte2 systems

Williams1 systems

Larimer1 systems

Caribou1 systems

Lawrence1 systems

Loudon1 systems

Weld1 systems

Pueblo1 systems