Los Angeles County, California — public water systems

277 active public water systems serve Los Angeles County, reporting 14M people served.

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

Active systems

277

Population served

14M

Community systems

199

Groundwater share

59.9%

Water systems in Los Angeles County

Active public water systems in Los Angeles County, California
#	Water system	County	Population served	Type	Source
1	Los Angeles-City, Dept. of Water & Power	Los Angeles	7,751,132	Community	Surface water
2	Long Beach Utilities Department	Los Angeles	466,772	Community	Purchased surface water
3	Santa Clarita Valley Water Agency	Los Angeles	294,090	Community	Surface water
4	Gswc - Southwest	Los Angeles	277,740	Community	Purchased surface water
5	San Gabriel Valley Water Co.-El Monte	Los Angeles	248,000	Community	Groundwater
6	Los Angeles Cwwd 40 Reg 4 & 34 Lancaster	Los Angeles	208,129	Community	Purchased surface water
7	Glendale-City, Water Dept.	Los Angeles	188,784	Community	Purchased surface water
8	Suburban Water Systems-San Jose	Los Angeles	168,843	Community	Purchased surface water
9	Pasadena Water and Power	Los Angeles	164,344	Community	Purchased surface water
10	California Water Service Co. - Ela	Los Angeles	152,474	Community	Purchased surface water
11	Pomona - City, Water Dept.	Los Angeles	151,713	Community	Surface water
12	California Water Service Co. - Dominguez	Los Angeles	143,996	Community	Purchased surface water
13	Palmdale Water Dist.	Los Angeles	126,804	Community	Surface water
14	Downey - City, Water Dept.	Los Angeles	110,556	Community	Groundwater
15	Azusa Light and Water	Los Angeles	110,044	Community	Surface water
16	Torrance-City, Water Dept.	Los Angeles	106,183	Community	Purchased surface water
17	Burbank-City, Water Dept.	Los Angeles	105,603	Community	Purchased surface water
18	Walnut Valley Water District	Los Angeles	100,941	Community	Purchased surface water
19	California Water Service Co. - Herm/Redo	Los Angeles	96,853	Community	Purchased surface water
20	Santa Monica-City, Water Division	Los Angeles	89,947	Community	Purchased surface water
21	Inglewood- City, Water Dept.	Los Angeles	80,824	Community	Purchased surface water
22	City of Alhambra	Los Angeles	79,776	Community	Purchased surface water
23	South Gate-City, Water Dept.	Los Angeles	76,443	Community	Purchased surface water
24	Compton-City, Water Dept.	Los Angeles	74,877	Community	Purchased surface water
25	Liberty Utilities - Bellflower-Norwalk	Los Angeles	72,624	Community	Purchased surface water
26	Las Virgenes Mwd	Los Angeles	72,602	Community	Surface water
27	California Water Service Co. - Palos Ver	Los Angeles	71,452	Community	Purchased surface water
28	Valley County Water Dist.	Los Angeles	68,871	Community	Groundwater
29	Lynwood-City, Water Dept.	Los Angeles	66,967	Community	Purchased surface water
30	Lakewood - City, Water Dept.	Los Angeles	66,135	Community	Groundwater
31	Suburban Water Systems-Whittier	Los Angeles	66,045	Community	Groundwater
32	Gswc - Florence/Graham	Los Angeles	63,500	Community	Purchased surface water
33	Monterey Park-City, Water Dept.	Los Angeles	62,183	Community	Groundwater
34	Suburban Water Systems-La Mirada	Los Angeles	56,793	Community	Purchased surface water
35	Gswc-San Dimas	Los Angeles	56,538	Community	Purchased surface water
36	Rowland Water District	Los Angeles	56,100	Community	Purchased surface water
37	Paramount - City, Water Dept.	Los Angeles	55,200	Community	Purchased surface water
38	Gswc - Bell, Bell Gardens	Los Angeles	54,877	Community	Purchased surface water
39	City of Arcadia	Los Angeles	51,361	Community	Groundwater
40	Gswc - Artesia	Los Angeles	50,375	Community	Groundwater
41	Whittier-City, Water Dept.	Los Angeles	49,954	Community	Groundwater
42	Glendora-City, Water Dept.	Los Angeles	49,934	Community	Purchased surface water
43	Cal/Am Water Company - San Marino	Los Angeles	47,995	Community	Purchased surface water
44	Cerritos - City, Water Dept.	Los Angeles	47,475	Community	Purchased surface water
45	Bellflower - Somerset Mwc	Los Angeles	46,300	Community	Purchased surface water
46	Hawthorne-City Water Dept.	Los Angeles	44,718	Community	Purchased surface water
47	Gswc - Norwalk	Los Angeles	43,176	Community	Purchased surface water
48	Pico Rivera - City, Water Dept.	Los Angeles	40,600	Community	Groundwater
49	Beverly Hills-City, Water Dept.	Los Angeles	40,121	Community	Purchased surface water
50	Gswc - Claremont	Los Angeles	39,730	Community	Purchased surface water