Census-designated place · New York
Water Mill, New York
Water Mill, census-designated place, in Suffolk County, New York. Water Mill had 2,506 residents in the 2020 Census, a full count; the ACS 2020-2024 5-year estimates put it at 2,764 (±556). GEOID 3678575.
Residents, 2020 Census
2,506
Census count or controlled total
ACS 2020-2024 estimate: 2,764 ±556
Median household income
$186,875
±$94,186 (90% margin)
New York: $85,974
Median home value
$2,000,000 or more
The survey's top or bottom value; no margin is published
New York: $423,800
Median gross rent
$3,200
±$1,340 (90% margin)
New York: $1,621
Where is Water Mill and what county is it in?
Water Mill is a census-designated place: an unincorporated community the Census Bureau draws for counting, with no city government of its own, in Suffolk County, New York. It covers 10.6 square miles of land, 237 residents per square mile in 2020.
Water Mill is in the New York-Newark-Jersey City, NY-NJ metropolitan statistical area, which takes in 22 counties (Census Bureau delineation, July 2023).
Water Mill lies entirely within the Town of Southampton, a town with its own local government (2020 census blocks).
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in Water Mill, and is it growing?
The 2020 Census counted 2,506 residents in Water Mill, a full count rather than a sample. The 2020-2024 American Community Survey, a sample, estimates 2,764 (±556).
The Census Bureau publishes yearly population estimates for incorporated places only; Water Mill is a census-designated place, so its figures come from the ACS and the 2020 Census.
| Measure | Water Mill | Suffolk County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 2,764 ±556 | 1,530,146 | +1,133 |
| Households | 1,280 ±319 | 512,565 | +604 |
| Average household size | 2.14 ±0.32 | 2.93 | no clear change |
| Housing units | 2,564 ±382 | 580,772 | +562 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); Census PEP Vintage 2025 (SUB-EST2025, CO-EST2025); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Water Mill?
The median resident of Water Mill is 54.9 years old; 12.2% are under 18 and 22.6% are 65 or older. The largest group is non-Hispanic white residents at 89.0%, then Hispanic or Latino residents (of any race) at 8.3%. 11.3% of residents were born outside the United States.
| Measure | Water Mill | Suffolk County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 54.9 ±6.3 | 41.7 | no clear change |
| Under 18 years | 12.2% ±6.1 pts | 20.8% | – |
| 65 years and over | 22.6% ±8.4 pts | 17.9% | – |
| Male | 48.2% ±6.3 pts | 49.6% | – |
| Hispanic or Latino (any race) | 8.3% ±9.0 pts | 22.8% | – |
| White alone, not Hispanic | 89.0% ±8.8 pts | 62.0% | no clear change |
| Black or African American alone, not Hispanic | 0.4% ±0.7 pts | 6.9% | – |
| Asian alone, not Hispanic | 1.5% ±1.0 pts | 4.4% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±1.5 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±1.5 pts | 0.0% | – |
| Two or more races, not Hispanic | 0.8% ±1.1 pts | 3.0% | – |
| Some other race alone, not Hispanic | 0.0% ±1.5 pts | 0.7% | – |
| Born outside the United States | 11.3% ±6.4 pts | 16.8% | no clear change |
| Speak a language other than English at home (age 5+) | 14.9% ±7.0 pts | 24.8% | – |
| Civilian veterans (age 18+) | 1.9% ±1.4 pts | 4.0% | – |
| With a disability | 8.9% ±8.0 pts | 10.5% | – |
| No health insurance coverage | 1.4% ±1.5 pts | 4.7% | – |
| High school graduate or higher (age 25+) | 97.7% ±2.0 pts | 90.4% | – |
| Bachelor's degree or higher (age 25+) | 73.0% ±10.1 pts | 40.2% | no clear change |
| Graduate or professional degree (age 25+) | 28.9% ±9.8 pts | 18.6% | – |
| Lived in the same house a year earlier | 85.8% ±10.4 pts | 92.8% | – |
| Moved from another state in the past year | 1.4% ±2.3 pts | 0.7% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Water Mill earn?
Half of Water Mill's 1,280 households earn less than $186,875 a year (±$94,186), against $130,686 in Suffolk County and $85,974 in New York. In 2015-2019 it was $191,100 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | Water Mill | Suffolk County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $186,875 ±$94,186 | $130,686 | no clear change |
| Mean household income | $327,147 ±$87,210 | $166,220 | – |
| Per capita income | $151,552 ±$42,505 | $57,164 | no clear change |
| People below the poverty line | 3.6% ±2.7 pts | 6.4% | – |
| Children under 18 below the poverty line | 0.0% ±11.9 pts | 7.1% | – |
| Households receiving SNAP | 0.0% ±3.3 pts | 7.2% | – |
| Households with a computer | 99.5% ±0.7 pts | 96.5% | – |
| Households with a broadband subscription | 85.3% ±15.6 pts | 93.2% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Water Mill?
Owners occupy 93.8% of Water Mill's occupied homes and renters 6.3%. The median owner-occupied home is valued at $2,000,000 or more by its owner (). The median renter pays $3,200 a month including utilities.
| Measure | Water Mill | Suffolk County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $2,000,000 or more | $578,400 | no clear change |
| Median gross rent | $3,200 ±$1,340 | $2,255 | – |
| Renters paying 35% or more of income on rent | 48.8% ±51.2 pts | 49.0% | – |
| Median monthly owner costs, with a mortgage | $4,000 or more | $3,320 | – |
| Owner-occupied homes | 93.8% ±5.6 pts | 82.2% | no clear change |
| Renter-occupied homes | 6.3% ±5.6 pts | 17.8% | – |
| Housing units | 2,564 ±382 | 580,772 | +562 |
| Homeowner vacancy rate | 0.3% ±0.6 pts | 0.6% | – |
| Rental vacancy rate | 4.8% ±9.8 pts | 4.1% | – |
| Single-family detached homes | 99.5% ±0.6 pts | 79.7% | – |
| Mobile homes | 0.2% ±0.5 pts | 1.3% | – |
| Built 2020 or later | 1.8% ±1.6 pts | 0.7% | – |
| Built 2010 to 2019 | 12.3% ±6.7 pts | 3.7% | – |
| Built 1939 or earlier | 9.8% ±4.3 pts | 9.1% | – |
| Households with no vehicle | 11.5% ±15.5 pts | 5.1% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How do people in Water Mill work and get to work?
48.8% of Water Mill's workers drive alone and 37.5% work from home. The average trip to work takes 18.6 minutes.
| Measure | Water Mill | Suffolk County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 64.9% ±8.5 pts | 65.5% | – |
| Unemployment rate | 6.0% ±4.3 pts | 4.7% | – |
| Drove alone to work | 48.8% ±12.6 pts | 72.1% | – |
| Carpooled | 0.0% ±2.8 pts | 7.5% | – |
| Public transportation | 5.0% ±3.7 pts | 4.8% | – |
| Walked | 6.7% ±5.0 pts | 1.4% | – |
| Worked from home | 37.5% ±15.2 pts | 12.0% | – |
| Mean travel time to work | 18.6 min ±4.9 | 31.1 min | no clear change |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What census tracts are in Water Mill?
1 census tract lies mostly in Water Mill, and 2 more reach into it (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 1907.13Suffolk County | 2,158 | $250,000 or more |
| Tract 1907.12Suffolk County | 1,306 | $186,906 |
| Tract 1907.06Suffolk County | 6,322 | $138,382 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 block assignment files (tract share = share of the tract's census blocks in Water Mill) · Census block assignment files
How does Water Mill compare with other places in New York?
Water Mill ranks 73rd of 1,623 places in New York with 1,000 or more residents and a reliable estimate, by median household income.
| Measure | Rank | Of |
|---|---|---|
| Population (ACS 2020-2024) | 974th | 1,657 |
| Residents per square mile | 1,000th | 1,657 |
| Median household income | 73rd | 1,623 |
| Per capita income | 12th | 1,653 |
| Median home value | 1st | 1,637 |
| Median gross rent | 42nd | 1,515 |
| Bachelor's degree or higher | 64th | 1,640 |
| Median age | 89th | 1,654 |
| Owner-occupied share | 115th | 1,639 |
| Work from home | 11th | 1,350 |
| Travel time to work | 1,477th | 1,652 |
Water Mill's figures with every place in New York (CSV)
Every place in New York, sortable · Compare Water Mill with other places
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How reliable are the figures for Water Mill?
25 of the 57 figures for Water Mill on this page carry a coefficient of variation over 40% and are marked with a ring: they come from a small sample, so read them as rough.
The American Community Survey samples about one household in eight over five years, so every figure is an estimate with a 90% margin of error (shown under each value). A ring marks an estimate whose coefficient of variation is over 40%. A change is called only when the gap between the two periods is larger than their combined 90% margin (the square root of the sum of the two squared margins), the Census Bureau's test. How to read a margin of error.
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026): margins of error as published · ACS technical documentation
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Water Mill are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.