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Windham County, Connecticut — public water systems

At a glance

254 active public water systems are filed under Windham County, Connecticut in EPA's SDWIS records, together reporting 63,868 people served. The largest is Windham Water Works, which reports serving 21,214 people. 53 are community water systems serving people where they live; the other 201 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.

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

Active systems

254

Population served

63.9K

Community systems

53

Groundwater share

99.2%

How does Windham County compare with other Connecticut counties?

Windham County has the 6th-most active public water systems among the 22 counties listed for active Connecticut systems in EPA records; among the 9 with 3 or more systems, the median has 277. Its systems report 63,868 people served in total, the 7th-largest county figure in the state and 2.2% of the statewide total. The average system here reports serving 251 people, well below the Connecticut average of 1,247. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.

Where does Windham County's drinking water come from?

By primary water source, Windham County's active systems draw on groundwater (252, 99%) and surface water (2, 0.8%). Overall, 99% rely mainly on groundwater (including purchased groundwater) and 0.8% on surface water, compared with 96% and 3.8% across Connecticut. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Windham Water Works, draws primarily on surface water.

What kinds of water systems operate in Windham County?

Windham County's active systems break down as 53 community systems (21%), 50 non-transient non-community systems (20%) and 151 transient non-community systems (59%). A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. EPA lists their owner types as private (87%), local government (12%) and state government (1.6%).

The 50 largest water systems in Windham County

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Active public water systems in Windham County, Connecticut
#Water systemCountyPopulation servedTypeSource
1Windham Water WorksWindham21,214CommunitySurface water
2Putnam Water Pollution Control AuthorityWindham7,300CommunitySurface water
3Ctwc - Crystal SystemWindham6,378CommunityGroundwater
4Ctwc - Gallup SystemWindham2,538CommunityGroundwater
5Ctwc - Plainfield SystemWindham1,713CommunityGroundwater
6Killingly High School & Agricultural CtrWindham1,400Non-transient non-communityGroundwater
7Woodstock AcademyWindham1,125Non-transient non-communityGroundwater
8Ctwc - Thompson SystemWindham1,070CommunityGroundwater
9Frito-LayWindham903Non-transient non-communityGroundwater
10Woodstock Elementary SchoolWindham636Non-transient non-communityGroundwater
11Woodstock Academy South CampusWindham620CommunityGroundwater
12Woodstock Middle SchoolWindham511Non-transient non-communityGroundwater
13Pomfret Community SchoolWindham500Non-transient non-communityGroundwater
14Parish Hill High SchoolWindham487Non-transient non-communityGroundwater
15North Windham Elementary SchoolWindham485Non-transient non-communityGroundwater
16Ashford SchoolWindham475Non-transient non-communityGroundwater
17Pomfret SchoolWindham400CommunityGroundwater
18Canterbury Elementary SchoolWindham350Non-transient non-communityGroundwater
19Camp Woodstock - Upper Main CampWindham346Transient non-communityGroundwater
20Hole in the Wall Gang Camp-Main System#1Windham335Transient non-communityGroundwater
21Ctwc - Ashford Park DivisionWindham334CommunityGroundwater
22Camp Woodstock - New Dining WellWindham322Transient non-communityGroundwater
23Camp ConnriWindham319Transient non-communityGroundwater
24Wyndham Park ApartmentsWindham312CommunityGroundwater
25Dr. Helen Baldwin SchoolWindham310Non-transient non-communityGroundwater
26Sterling Water SystemWindham308CommunityGroundwater
27The Rectory SchoolWindham300CommunityGroundwater
28Chaplin Elementary SchoolWindham280Non-transient non-communityGroundwater
29Whitcraft LLCWindham272Non-transient non-communityGroundwater
30Moosup Garden ApartmentsWindham270CommunityGroundwater
31Marianapolis Prep School - Admin/SchoolWindham266Non-transient non-communityGroundwater
32Matulaitis Nursing HomeWindham254CommunityGroundwater
33Rogers Corp - Rogers WellWindham250Non-transient non-communityGroundwater
34Eastford Elementary SchoolWindham225Non-transient non-communityGroundwater
35Hampton Elementary SchoolWindham220Non-transient non-communityGroundwater
36Peake Brook LLCWindham208Non-transient non-communityGroundwater
37Quinebaug Mobile Home ParkWindham205CommunityGroundwater
38Scotland Elementary SchoolWindham200Non-transient non-communityGroundwater
39Woodstock Meadows Condominium Assn.Windham180CommunityGroundwater
40Linemaster Switch CorpWindham178Non-transient non-communityGroundwater
41Tri-State Baptist ChurchWindham157Transient non-communityGroundwater
42Campbell Heights ApartmentsWindham152CommunityGroundwater
43New England Laborers Academy - Main SysWindham151Non-transient non-communityGroundwater
44Evangelical Christian Center -Rec CenterWindham150Transient non-communityGroundwater
45Solair Recreational League - Lower RidgeWindham150Non-transient non-communityGroundwater
46Inn at Woodstock HillWindham145Transient non-communityGroundwater
47Perry Hill Estates Apartments Inc..Windham144CommunityGroundwater
48Ashford Hills ApartmentsWindham136CommunityGroundwater
49Douglas ManorWindham135CommunityGroundwater
50Birch Hills CondominiumsWindham132CommunityGroundwater

All other water systems in Windham County (204)

The remaining active systems filed under Windham County, largest first, with the population each reports serving.

Windham County water systems: frequently asked questions

How many public water systems are in Windham County, Connecticut?

EPA's SDWIS records file 254 active public water systems under Windham County, Connecticut: 53 community systems (21%), 50 non-transient non-community systems (20%) and 151 transient non-community systems (59%).

Who supplies drinking water in Windham County, CT?

The largest community water systems filed under Windham County are Windham Water Works (21,214 people served), Putnam Water Pollution Control Authority (7,300 people served) and Ctwc - Crystal System (6,378 people served). Which system serves a particular address depends on its service area, which EPA's SDWIS records do not include; a water bill or the local utility can confirm it.

Does Windham County's drinking water come from groundwater or surface water?

Of the 254 active public water systems in Windham County, 99% draw mainly on groundwater and 0.8% on surface water, counting purchased supplies. The largest system, Windham Water Works, uses surface water.

Where can I find a water quality report for Windham County?

Each community water system must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1, covering the previous calendar year. 53 community systems are filed under Windham County, so the report to look for is the one from the system that supplies your address.

How can I check violations for a water system in Windham County?

Open the system's profile from the list on this page. Each profile shows the most recent Safe Drinking Water Act violations in EPA's records, with plain-English labels and whether each one is resolved. For current compliance status, EPA ECHO is the primary source.

More Connecticut water systems

About this data

Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.

Cite as: AquaCensus, “Public water systems in Windham County, Connecticut”, https://aquacensus.com/water-systems/connecticut/windham (data as of October 1, 2026).