Nantucket County, Massachusetts — public water systems
At a glance
5 active public water systems are filed under Nantucket County, Massachusetts in EPA's SDWIS records, together reporting 32,563 people served. The largest is Wannacomet Water Company, which reports serving 27,703 people. 2 are community water systems serving people where they live; the other 3 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
5
Population served
32.6K
Community systems
2
Groundwater share
100%
How does Nantucket County compare with other Massachusetts counties?
Nantucket County has the 15th-most active public water systems among the 33 counties listed for active Massachusetts systems in EPA records; among the 16 with 3 or more systems, the median has 104. Its systems report 32,563 people served in total, the 14th-largest county figure in the state and 0.3% of the statewide total. The average system here reports serving 6,513 people, roughly in line with the Massachusetts average of 6,275. 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 Nantucket County's drinking water come from?
By primary water source, Nantucket County's active systems draw on groundwater (5, 100%). Overall, all rely mainly on groundwater (including purchased groundwater) and none on surface water, compared with 88% and 12% across Massachusetts. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Wannacomet Water Company, draws primarily on groundwater.
What kinds of water systems operate in Nantucket County?
Nantucket County's active systems break down as 2 community systems (40%) and 3 transient non-community systems (60%). 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 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 local government (60%) and private (40%).
Water systems in Nantucket County
🔒 Create a free account to export CSV| # | Water system | County | Population served | Type | Source |
|---|---|---|---|---|---|
| 1 | Wannacomet Water Company | Nantucket | 27,703 | Community | Groundwater |
| 2 | Siasconset Water Department | Nantucket | 3,000 | Community | Groundwater |
| 3 | Surfside Beach | Nantucket | 1,500 | Transient non-community | Groundwater |
| 4 | Wauwinet House | Nantucket | 300 | Transient non-community | Groundwater |
| 5 | Sankaty Head Golf Club Inc.. | Nantucket | 60 | Transient non-community | Groundwater |
Nantucket County water systems: frequently asked questions
How many public water systems are in Nantucket County, Massachusetts?
EPA's SDWIS records file 5 active public water systems under Nantucket County, Massachusetts: 2 community systems (40%) and 3 transient non-community systems (60%).
Who supplies drinking water in Nantucket County, MA?
The largest community water systems filed under Nantucket County are Wannacomet Water Company (27,703 people served) and Siasconset Water Department (3,000 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 Nantucket County's drinking water come from groundwater or surface water?
Of the 5 active public water systems in Nantucket County, all draw mainly on groundwater and none on surface water, counting purchased supplies. The largest system, Wannacomet Water Company, uses groundwater.
Where can I find a water quality report for Nantucket 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. 2 community systems are filed under Nantucket 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 Nantucket 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 Massachusetts 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 Nantucket County, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/nantucket (data as of October 1, 2026).