How many public water systems are in Maine?

Maine has 1,866 active public water systems in EPA SDWIS records, including 385 community water systems. Together they report serving 937.4K people.

What is the largest water system in Maine?

Portland Water District-Greater is the largest active public water system in Maine, serving a reported 135,068 people.

Does Maine rely more on groundwater or surface water?

96.3% of Maine's active public water systems draw primarily on groundwater and 3.7% on surface water (including purchased supplies).

Maine public water systems

1,866 active systems regulated under the Safe Drinking Water Act, serving a reported 937.4K people across 17 counties.

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

Active systems

1,866

Population served

937.4K

Community systems

385

Groundwater share

96.3%

System types in Maine

385

Community water system

387

Non-transient non-community water system

1,094

Transient non-community water system

Largest water systems in Maine

The largest active public water systems in Maine by population served
#	Water system	County	Population served	Type	Source
1	Portland Water District-Greater	Cumberland	135,068	Community	Surface water
2	Maine Water Company Biddeford Saco Div	York	42,508	Community	Surface water
3	Kennebunk, Kennebunkport & Wells Wd	York	35,663	Community	Surface water
4	Bangor Water District	Penobscot	27,298	Community	Surface water
5	Lewiston Water & Sewer Division	Androscoggin	23,720	Community	Surface water
6	Kennebec Water District	Kennebec	22,060	Community	Surface water
7	Maine Water Company Camden & Rockland	Knox	21,315	Community	Surface water
8	Brunswick/Topsham Water District	Cumberland	18,863	Community	Groundwater
9	Auburn Water District	Androscoggin	17,245	Community	Surface water
10	Kittery Water District	York	14,478	Community	Surface water
11	Sanford Water District	York	14,328	Community	Groundwater
12	Greater Augusta Utility District	Kennebec	13,750	Community	Groundwater
13	York Water District	York	13,675	Community	Surface water
14	Bath Water District	Sagadahoc	9,290	Community	Surface water
15	Gardiner Water District	Kennebec	9,000	Community	Groundwater
16	Brewer Water Department	Penobscot	8,860	Community	Surface water
17	Boothbay Region Water District	Lincoln	8,448	Community	Surface water
18	Yarmouth Water District	Cumberland	8,000	Community	Groundwater
19	Old Town Water District	Penobscot	7,648	Community	Groundwater
20	Lisbon Water Department	Androscoggin	6,643	Community	Groundwater
21	Presque Isle Utilities District	Aroostook	6,128	Community	Groundwater under influence of surface water
22	Maine Water Company Skowhegan Division	Somerset	6,105	Community	Surface water
23	Orono-Veazie Water District	Penobscot	5,793	Community	Groundwater
24	Belfast Water District	Waldo	5,698	Community	Groundwater
25	Anson and Madison Water District	Somerset	5,568	Community	Surface water

By county

Cumberland224 systems Hancock201 systems York191 systems Kennebec169 systems Penobscot168 systems Oxford135 systems Aroostook122 systems Washington109 systems Somerset100 systems Androscoggin94 systems Lincoln84 systems Waldo77 systems Franklin63 systems Knox47 systems Piscataquis42 systems Sagadahoc39 systems

Caroline1 systems