Cook County, Illinois — public water systems

303 active public water systems serve Cook County, reporting 5.3M people served.

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

Active systems

303

Population served

5.3M

Community systems

161

Groundwater share

48.2%

Water systems in Cook County

Active public water systems in Cook County, Illinois
#	Water system	County	Population served	Type	Source
1	Chicago	Cook	2,746,388	Community	Surface water
2	Cicero	Cook	83,000	Community	Purchased surface water
3	Schaumburg	Cook	75,750	Community	Purchased surface water
4	Evanston	Cook	74,486	Community	Surface water
5	Arlington Heights	Cook	73,320	Community	Purchased surface water
6	Palatine	Cook	70,875	Community	Purchased surface water
7	Skokie	Cook	66,422	Community	Purchased surface water
8	Des Plaines	Cook	60,675	Community	Purchased surface water
9	Oak Lawn	Cook	58,362	Community	Purchased surface water
10	Orland Park	Cook	58,020	Community	Purchased surface water
11	Berwyn	Cook	57,250	Community	Purchased surface water
12	Tinley Park	Cook	56,703	Community	Purchased surface water
13	Oak Park	Cook	54,583	Community	Purchased surface water
14	Hoffman Estates	Cook	50,179	Community	Purchased surface water
15	Glenview	Cook	47,856	Community	Purchased surface water
16	Buffalo Grove	Cook	43,212	Community	Purchased surface water
17	Bartlett	Cook	41,500	Community	Purchased surface water
18	Mount Prospect	Cook	41,000	Community	Purchased surface water
19	Park Ridge	Cook	39,800	Community	Purchased surface water
20	Wheeling	Cook	39,725	Community	Purchased surface water
21	Streamwood	Cook	39,577	Community	Purchased surface water
22	Hanover Park	Cook	37,470	Community	Purchased surface water
23	Calumet City	Cook	37,000	Community	Purchased surface water
24	Elk Grove Village	Cook	34,700	Community	Purchased surface water
25	Northbrook	Cook	34,407	Community	Surface water
26	Aqua Illinois-North Maine Utilities	Cook	30,043	Community	Purchased surface water
27	South Stickny Sd	Cook	30,000	Community	Purchased surface water
28	Niles	Cook	29,350	Community	Purchased surface water
29	Lansing	Cook	29,076	Community	Purchased surface water
30	Oak Forest	Cook	27,478	Community	Purchased surface water
31	Wilmette	Cook	27,087	Community	Surface water
32	Chicago Heights	Cook	26,184	Community	Purchased surface water
33	Morton Grove	Cook	25,297	Community	Purchased surface water
34	Harvey	Cook	25,000	Community	Purchased surface water
35	Elmwood Park	Cook	25,000	Community	Purchased surface water
36	Melrose Park	Cook	24,206	Community	Purchased surface water
37	Maywood	Cook	24,090	Community	Purchased surface water
38	Rolling Meadows	Cook	23,329	Community	Purchased surface water
39	South Holland	Cook	22,000	Community	Purchased surface water
40	Park Forest	Cook	21,687	Community	Groundwater
41	Blue Island	Cook	21,494	Community	Purchased surface water
42	Dolton	Cook	20,510	Community	Purchased surface water
43	Evergreen Park	Cook	19,943	Community	Purchased surface water
44	Homewood	Cook	19,463	Community	Purchased surface water
45	Bellwood	Cook	19,156	Community	Purchased surface water
46	Alsip	Cook	19,063	Community	Purchased surface water
47	Brookfield	Cook	18,776	Community	Purchased surface water
48	Palos Hills	Cook	18,530	Community	Purchased surface water
49	Franklin Park	Cook	18,467	Community	Purchased surface water
50	Justice-Willow Springs Water Commission	Cook	18,457	Community	Purchased surface water