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Tompkins County, New York — public water systems

At a glance

111 active public water systems are filed under Tompkins County, New York in EPA's SDWIS records, together reporting 102,856 people served. The largest is Cornell University, which reports serving 31,581 people. 51 are community water systems serving people where they live; the other 60 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

111

Population served

102.9K

Community systems

51

Groundwater share

91.9%

How does Tompkins County compare with other New York counties?

Tompkins County has the 28th-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 102,856 people served in total, the 26th-largest county figure in the state and 0.5% of the statewide total. The average system here reports serving 927 people, about 61% 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 Tompkins County's drinking water come from?

By primary water source, Tompkins County's active systems draw on groundwater (96, 86%), groundwater under influence of surface water (6, 5.4%), purchased surface water (6, 5.4%) and surface water (3, 2.7%). Overall, 92% rely mainly on groundwater (including purchased groundwater) and 8.1% 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, Cornell University, draws primarily on surface water.

What kinds of water systems operate in Tompkins County?

Tompkins County's active systems break down as 51 community systems (46%), 11 non-transient non-community systems (9.9%) and 49 transient non-community systems (44%). 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 (81%), local government (12%), public/private partnership (4.5%) and state government (2.7%).

The 50 largest water systems in Tompkins County

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Active public water systems in Tompkins County, New York
#Water systemCountyPopulation servedTypeSource
1Cornell UniversityTompkins31,581CommunitySurface water
2Ithaca CityTompkins29,457CommunitySurface water
3Ithaca Town WdTompkins13,000CommunityPurchased surface water
4Cayuga Heights VillageTompkins3,170CommunityPurchased surface water
5Lansing (V)Tompkins3,100CommunityPurchased surface water
6Lansing (T) Consolidated WdTompkins3,000CommunityPurchased surface water
7Groton VillageTompkins2,470CommunityGroundwater under influence of surface water
8Newfield WdsTompkins2,300CommunityGroundwater
9Trumansburg VillageTompkins2,300CommunityGroundwater
10Dryden VillageTompkins2,000CommunityGroundwater
11Dryden WdTompkins725CommunityPurchased surface water
12Pinecreek CampgroundTompkins495Transient non-communityGroundwater
13Hanshaw Village MHPTompkins447CommunityGroundwater
14Treman State Park-UpperTompkins400Transient non-communityGroundwater
15Ulysses Wd #3Tompkins400CommunityPurchased surface water
16Caroline Elementary SchoolTompkins350Non-transient non-communityGroundwater
17Ithaca EstatesTompkins342CommunityGroundwater
18Enfield Elementary SchoolTompkins282Non-transient non-communityGroundwater
19West Danby WdTompkins265CommunityGroundwater
20Country Acres MHPTompkins253CommunityGroundwater
21Little Creek MHPTompkins252CommunityGroundwater
22William George AgencyTompkins250CommunityGroundwater
23Yellow Barn WdTompkins250CommunityGroundwater
24Village TaqueriaTompkins220Transient non-communityGroundwater
25Sandy Creek Mobile Home ParkTompkins215CommunityGroundwater
26Dandy Mini Mart #33-CTompkins200Transient non-communityGroundwater
27Buttermilk Falls State Park - UpperTompkins200Transient non-communityGroundwater
28Dandy Mini-Mart #47-FTompkins200Transient non-communityGroundwater
29Newfield EstatesTompkins160CommunityGroundwater
30Mclean-Cassavant Elementary SchoolTompkins152Non-transient non-communityGroundwater
31Spruce Row CampgroundTompkins150Transient non-communityGroundwater
32Elm Tree InnTompkins129Transient non-communityGroundwater
33Pleasant View MHPTompkins125CommunityGroundwater
34Beaconview MHPTompkins110CommunityGroundwater
35Stork H & E Turbo BladingTompkins110Non-transient non-communityGroundwater
36Creekwood ApartmentsTompkins110CommunityGroundwater
37Country Gardens ApartmentsTompkins110CommunityGroundwater
38Franziska Racker CentersTompkins100Non-transient non-communityGroundwater
39Willow Glen Christian SchoolTompkins100Non-transient non-communityGroundwater
40Dandy Mini Mart #77-ETompkins100Transient non-communityGroundwater
41Ithaca Yacht ClubTompkins100Transient non-communityGroundwater
42Frosty CowTompkins100Transient non-communityGroundwater
43Groton Golf and Recreation AssociationTompkins100Transient non-communityGroundwater
44Subway DrydenTompkins100Transient non-communityGroundwater
45Khmer AngkorTompkins100Transient non-communityGroundwater
46Freeville Elementary SchoolTompkins95Non-transient non-communityGroundwater
47Fall Creek ParkTompkins90CommunityGroundwater under influence of surface water
48Seabring InnTompkins80Transient non-communityGroundwater
49Hillview Terrace MHPTompkins80CommunityGroundwater
50Hillendale Golf CourseTompkins75Transient non-communityGroundwater

All other water systems in Tompkins County (60)

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

Tompkins County water systems: frequently asked questions

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

EPA's SDWIS records file 111 active public water systems under Tompkins County, New York: 51 community systems (46%), 11 non-transient non-community systems (9.9%) and 49 transient non-community systems (44%).

Who supplies drinking water in Tompkins County, NY?

The largest community water systems filed under Tompkins County are Cornell University (31,581 people served), Ithaca City (29,457 people served) and Ithaca Town Wd (13,000 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 Tompkins County's drinking water come from groundwater or surface water?

Of the 111 active public water systems in Tompkins County, 92% draw mainly on groundwater and 8.1% on surface water, counting purchased supplies. The largest system, Cornell University, uses surface water.

Where can I find a water quality report for Tompkins 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. 51 community systems are filed under Tompkins 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 Tompkins 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 Tompkins County, New York”, https://aquacensus.com/water-systems/new-york/tompkins (data as of October 1, 2026).