Grant County, Washington — public water systems

265 active public water systems serve Grant County, reporting 144K people served.

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

Active systems

265

Population served

144K

Community systems

Groundwater share

100%

Water systems in Grant County

Active public water systems in Grant County, Washington
#	Water system	County	Population served	Type	Source
1	Moses Lake City of	Grant	32,428	Community	Groundwater
2	Gorge Amphitheatre	Grant	25,119	Transient non-community	Groundwater
3	Ephrata Water Department	Grant	8,718	Community	Groundwater
4	Quincy Water Department City of	Grant	8,415	Community	Groundwater
5	Mattawa City of	Grant	5,370	Community	Groundwater
6	Sun Lakes State Park	Grant	4,858	Transient non-community	Groundwater
7	Warden City of	Grant	4,674	Community	Groundwater
8	Royal City Water	Grant	3,389	Community	Groundwater
9	Steamboat Rock State Park #1	Grant	2,907	Transient non-community	Groundwater
10	Desert Aire Owner Assn	Grant	2,856	Community	Groundwater
11	Soap Lake Water Dept	Grant	2,399	Community	Groundwater
12	Electric City City of	Grant	1,812	Community	Groundwater
13	Sunland Estates Homeowners Assn	Grant	1,480	Community	Groundwater
14	Potholes State Park	Grant	1,456	Transient non-community	Groundwater
15	Grand Coulee Water Dept City of	Grant	1,428	Community	Purchased groundwater
16	Pelican Point By Cascadia LLC	Grant	1,357	Community	Groundwater
17	Lakeview Park Water Assn	Grant	1,259	Community	Groundwater
18	Weiler-Martin Tracts Water Assn	Grant	1,163	Community	Groundwater
19	Basin Water Sources Inc.	Grant	1,158	Community	Groundwater
20	Crescent Bar System	Grant	1,108	Community	Groundwater
21	George City of	Grant	1,035	Community	Groundwater
22	Sunserra at Crescent Bar	Grant	1,000	Community	Groundwater
23	Coulee City Town of	Grant	944	Community	Groundwater
24	Winchester Wb Rest Area	Grant	944	Transient non-community	Groundwater
25	Winchester Eb Rest Area	Grant	903	Transient non-community	Groundwater
26	Potholes General Store	Grant	877	Transient non-community	Groundwater
27	Ephrata Raceway Park	Grant	700	Transient non-community	Groundwater
28	Quincy Valley Rest Area	Grant	536	Transient non-community	Groundwater
29	Dry Falls State Park	Grant	519	Transient non-community	Groundwater
30	Port of Royal Slope	Grant	447	Non-transient non-community	Groundwater
31	Royal Water District	Grant	430	Community	Groundwater
32	Wilson Creek Water Dept Town of	Grant	386	Community	Groundwater
33	Cascade Valley Water District	Grant	379	Community	Groundwater
34	Jr Simplot Co	Grant	365	Non-transient non-community	Groundwater
35	Smokiam Rv Resort	Grant	343	Transient non-community	Groundwater
36	Deep Lake State Park	Grant	323	Transient non-community	Groundwater
37	Stratford Road Estates	Grant	312	Community	Groundwater
38	Green Acres Orchard	Grant	308	Non-transient non-community	Groundwater
39	Wanapum Village	Grant	305	Community	Groundwater
40	Hillcrest Water Users Assn	Grant	300	Community	Groundwater
41	Midway Mini-Mart	Grant	293	Transient non-community	Groundwater
42	Skyline Water System Inc.	Grant	293	Community	Groundwater
43	Green Acres - Mattawa	Grant	271	Non-transient non-community	Groundwater
44	Parker Spring Acres Water Assoc	Grant	255	Community	Groundwater
45	Sunrise Water Association	Grant	250	Community	Groundwater
46	Hartline Water System	Grant	249	Community	Groundwater
47	Crescent View Condominium Owners	Grant	243	Community	Groundwater
48	Ridgeview Estates Water Association	Grant	240	Community	Groundwater
49	Sentinel Gap Water Assn	Grant	226	Community	Groundwater
50	Grove Terrace MHP Two LLC	Grant	220	Community	Groundwater