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Jefferson County, New York — public water systems

At a glance

157 active public water systems are filed under Jefferson County, New York in EPA's SDWIS records, together reporting 130,600 people served. The largest is Fort Drum, which reports serving 34,000 people. 57 are community water systems serving people where they live; the other 100 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

157

Population served

130.6K

Community systems

57

Groundwater share

66.9%

How does Jefferson County compare with other New York counties?

Jefferson County has the 17th-most active public water systems among the 100 counties listed for active New York systems in EPA records; among the 64 with 3 or more systems, the median has 94. Its systems report 130,600 people served in total, the 21st-largest county figure in the state and 0.7% of the statewide total. The average system here reports serving 832 people, about 65% below the New York average of 2,374. 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 Jefferson County's drinking water come from?

By primary water source, Jefferson County's active systems draw on groundwater (90, 57%), surface water (30, 19%), purchased surface water (22, 14%) and groundwater under influence of surface water (8, 5.1%). Overall, 67% rely mainly on groundwater (including purchased groundwater) and 33% on surface water, compared with 91% and 8.5% across New York. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Fort Drum, draws primarily on purchased surface water.

What kinds of water systems operate in Jefferson County?

Jefferson County's active systems break down as 57 community systems (36%), 4 non-transient non-community systems (2.5%) and 96 transient non-community systems (61%). 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 (59%), local government (29%), state government (7%) and public/private partnership (2.5%).

The 50 largest water systems in Jefferson County

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Active public water systems in Jefferson County, New York
#Water systemCountyPopulation servedTypeSource
1Fort DrumJefferson34,000CommunityPurchased surface water
2Watertown CityJefferson27,861CommunitySurface water
3Leray Town Wd 1, 2, 4Jefferson7,140CommunityGroundwater
4Carthage VillageJefferson3,600CommunitySurface water
5Cape Vincent Town Wd 1 & 5Jefferson2,600CommunityPurchased surface water
6Sackets Harbor VillageJefferson2,200CommunitySurface water
7Clayton VillageJefferson2,100CommunitySurface water
8Can-Am SpeedwayJefferson2,000Transient non-communityGroundwater
9Adams VillageJefferson2,000CommunityGroundwater
10Alexandria Bay VillageJefferson1,900CommunitySurface water
11Pamelia Town Wd 4 & 5Jefferson1,857CommunityPurchased surface water
12Philadelphia VillageJefferson1,800CommunityGroundwater under influence of surface water
13West Carthage VillageJefferson1,734CommunityPurchased surface water
14Black River VillageJefferson1,600CommunityGroundwater
15Stone Mills MuseumJefferson1,500Transient non-communityGroundwater
16Cape Vincent VillageJefferson1,500CommunitySurface water
17Rutland Town Wd 1Jefferson1,500CommunityPurchased groundwater
18Ellisburg Wd 1, 2 & 3Jefferson1,500CommunityGroundwater
19Brownville VillageJefferson1,200CommunityGroundwater
20Dexter VillageJefferson1,100CommunityGroundwater
21Adams T Wd 1,2,3 (Adams Center)Jefferson1,000CommunityPurchased groundwater
22Wellesley Island State ParkJefferson1,000Transient non-communityGroundwater
23Tiba - Boldt CastleJefferson1,000Transient non-communitySurface water
24Theresa VillageJefferson950CommunityPurchased groundwater
25Antwerp VillageJefferson900CommunityGroundwater
26Thousand Island Park Corp.Jefferson900Transient non-communitySurface water
27Cape Vincent Town Wd 3, 4, & 6Jefferson770CommunityPurchased surface water
28Watertown Town Wd 3 & 4 & 5Jefferson750CommunityPurchased surface water
29Orleans Town Wd 1 (Lafargeville)Jefferson750CommunityGroundwater
30Hounsfield Wd 2Jefferson725CommunityPurchased surface water
31Henderson Town Wd 1,2Jefferson700CommunitySurface water
32Orleans Town Wd 2 (Rt 12)Jefferson690CommunityPurchased surface water
33Champion Wd 2, 4 & 5Jefferson650CommunityGroundwater
34Evans Mills VillageJefferson644CommunityGroundwater
35Chaumont VillageJefferson625CommunityPurchased surface water
36Brownville (T) Wd #1Jefferson600CommunityPurchased surface water
37Kring Point State ParkJefferson600Transient non-communitySurface water
38Watertown Town Wd 1 & 2Jefferson600CommunityPurchased surface water
39Wellesley Island Water Corp.Jefferson548CommunitySurface water
40Northland EstatesJefferson540CommunityGroundwater
41Southwick Beach State ParkJefferson520Transient non-communitySurface water
42Alexandria Town Wd #2 - RedwoodJefferson500CommunityPurchased surface water
43Glen Park VillageJefferson500CommunityPurchased groundwater
44Leray Town Wd 3Jefferson480CommunityPurchased groundwater
45Hounsfield Wd 1, 5Jefferson480CommunityPurchased surface water
46Mannsville VillageJefferson450CommunityGroundwater under influence of surface water
47Deferiet VillageJefferson420CommunityGroundwater
48Creekstone FarmsJefferson400Transient non-communityGroundwater
49Champion Wd 1 (Great Bend)Jefferson400CommunityPurchased groundwater
50Lyme Town Wd 2Jefferson400CommunityPurchased surface water

All other water systems in Jefferson County (105)

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

Jefferson County water systems: frequently asked questions

How many public water systems are in Jefferson County, New York?

EPA's SDWIS records file 157 active public water systems under Jefferson County, New York: 57 community systems (36%), 4 non-transient non-community systems (2.5%) and 96 transient non-community systems (61%).

Who supplies drinking water in Jefferson County, NY?

The largest community water systems filed under Jefferson County are Fort Drum (34,000 people served), Watertown City (27,861 people served) and Leray Town Wd 1, 2, 4 (7,140 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 Jefferson County's drinking water come from groundwater or surface water?

Of the 157 active public water systems in Jefferson County, 67% draw mainly on groundwater and 33% on surface water, counting purchased supplies. The largest system, Fort Drum, uses purchased surface water.

Where can I find a water quality report for Jefferson 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. 57 community systems are filed under Jefferson 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 Jefferson 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 New York 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 Jefferson County, New York”, https://aquacensus.com/water-systems/new-york/jefferson (data as of October 1, 2026).