How old are the homes in Mount Sinai, NY?

Name: Age of homes in Mount Sinai, NY, 2020–2024
Creator: US Census Bureau
License: https://www.census.gov/data/developers/about/terms-of-service.html

41.3% (±5.5 points) of the homes in Mount Sinai, NY were built before 1980 (2020–2024 American Community Survey).

3.2% were built before 1940.

9.1% were built in 2010 or later.

Figures last updated on November 12, 2026.

Built before 1980: 41.3% (±5.5 points)
Built before 1940: 3.2%
Built 2010 or later: 9.1%

When the homes in Mount Sinai were built

Housing units by year structure built, 2020–2024
Year built	Mount Sinai	Suffolk County	New York	United States
2020 or later	6.3% (±3.2 points)	0.7%	0.8%	2.0%
2010 to 2019	2.8% (±1.6 points)	3.7%	5.3%	9.4%
2000 to 2009	32.8% (±5.5 points)	8.3%	6.4%	13.6%
1990 to 1999	4.9% (±1.9 points)	8.9%	5.9%	12.4%
1980 to 1989	11.9% (±3.9 points)	10.2%	7.7%	12.9%
1970 to 1979	30.7% (±4.3 points)	17.8%	9.8%	14.2%
1960 to 1969	5.0% (±2.6 points)	19.7%	12.1%	9.9%
1950 to 1959	2.3% (±1.4 points)	17.2%	14.1%	9.5%
1940 to 1949	0.1% (±0.2 points)	4.5%	7.6%	4.4%
1939 or earlier	3.2% (±1.7 points)	9.1%	30.3%	11.7%

In Mount Sinai, the share of homes built before 1980 is lower than in Suffolk County (68.3%).

It is also lower than in New York (73.9%).

It is lower than the national figure (49.7%).

In Suffolk County, Mount Sinai ranks 98 of 112 places with a published estimate, from highest to lowest share of homes built before 1980.

Statewide, it ranks 373 of 414.

Rankings use the estimates alone; where margins of error overlap, neighboring ranks may not truly differ.

Why the age of a home matters: lead-based paint

Federal law treats housing built before 1978 as likely to contain lead-based paint.

Before a lease or sale of most pre-1978 housing, the landlord or seller must disclose any known lead-based paint and hazards and give the tenant or buyer the EPA pamphlet (42 U.S.C. § 4852d; 40 CFR part 745, subpart F; 24 CFR part 35, subpart A).

A contractor paid to renovate, repair or paint a pre-1978 home must be a certified firm, use a certified renovator and follow lead-safe work practices under the Renovation, Repair and Painting Rule (40 CFR part 745, subpart E) whenever the job disturbs more than 6 square feet of painted surface in a room or more than 20 square feet outside; window replacement and demolition always count (40 CFR 745.83).

Certification comes from EPA, or from the state where EPA has authorized the state to run the program.

The Census Bureau groups construction by decade, so the share built before 1978 lies between the share built before 1970 (10.6%) and the share built before 1980 (41.3%).

Homes built before 1980 in places near Mount Sinai

Nearest places with a published estimate, compared with Mount Sinai
Place	Distance	Homes built before 1980	Compared with this place
Mount Sinai	—	41.3% (±5.5 points)	—
Miller Place	1.4 mi	56.7% (±10.9 points)	Higher
Village of Port Jefferson	1.7 mi	58.4% (±9.3 points)	Higher
Port Jefferson Station	2.6 mi	70.1% (±11.1 points)	Higher
Terryville	2.7 mi	68.5% (±10.2 points)	Higher
Village of Belle Terre	2.8 mi	81.4% (±16.4 points)	Higher
Sound Beach	3.0 mi	84.7% (±15.6 points)	Higher
Village of Poquott	3.8 mi	60.2% (±12.9 points)	Higher
East Setauket	4.1 mi	69.5% (±9.4 points)	Higher

Nearby places with a measurably higher figure: Miller Place, NY (56.7%), Village of Port Jefferson, NY (58.4%), Port Jefferson Station, NY (70.1%).

Distance is measured in a straight line between the Census Bureau’s internal points for each place.

Homes built before 1980 across Suffolk County, place by place

Rank	Place	Homes built before 1980
92	Melville	47.9% (±5.2 points)
93	Riverhead (community)	47.3% (±8.8 points)
94	East Quogue	47.1% (±9.2 points)
95	Noyack	46.8% (±9.9 points)
96	Shelter Island Heights	43.1% (±13.3 points)
97	Westhampton	41.5% (±9.7 points)
98	Mount Sinai	41.3% (±5.5 points)
99	Baiting Hollow	41.1% (±9.5 points)
100	Calverton	40.7% (±9.5 points)
101	North Sea	40.6% (±9.5 points)
102	Northwest Harbor	39.1% (±10.9 points)
103	Remsenburg-Speonk	37.8% (±10.0 points)
104	Shinnecock Hills	35.8% (±10.8 points)

Showing 13 of 112 places in Suffolk County, ranked from highest to lowest.

Mount Sinai is a census-designated place: an unincorporated community the Census Bureau draws for statistics, with no municipal government of its own.

It lies inside the Town of Brookhaven, whose figures include it.

Survey years: 2020–2024 (American Community Survey 5-year estimates).

Margins of error are at the 90% confidence level.

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Questions about Mount Sinai

How old are most homes in Mount Sinai?

41.3% of homes in Mount Sinai, NY were built before 1980 (2020–2024 American Community Survey).

Do homes in Mount Sinai need a lead paint disclosure?

A home built before 1978 does, before it is rented or sold, unless an exemption applies (42 U.S.C. § 4852d); between 10.6% and 41.3% of homes in Mount Sinai were built before then.

Does a contractor need lead certification to work on older homes in Mount Sinai?

Yes, when the job disturbs more than 6 square feet of paint in a room or 20 square feet outside, or replaces a window: the firm must be certified and a certified renovator must direct the work under the Renovation, Repair and Painting Rule (40 CFR part 745, subpart E).

Sources

Selected Housing Characteristics (DP04), 2020–2024 ACS 5-year estimates — Mount Sinai CDP, New York

To check these figures in the Census Bureau’s own API, request the variables below from the 2024 ACS 5-year data profile (acs/acs5/profile) for Mount Sinai CDP, New York (place:49066, in state:36).

Each estimate (E or PE) has a margin of error beside it (M or PM).

The API needs a free key.

Request a Census API key.

DP04_0017PE, DP04_0017PM, DP04_0018PE, DP04_0018PM, DP04_0019PE, DP04_0019PM, DP04_0020PE, DP04_0020PM, DP04_0021PE, DP04_0021PM, DP04_0022PE, DP04_0022PM, DP04_0023PE, DP04_0023PM, DP04_0024PE, DP04_0024PM, DP04_0025PE, DP04_0025PM, DP04_0026PE, DP04_0026PM

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.

Figures are published by the US Census Bureau, HUD, the Bureau of Labor Statistics and the FBI; Seayora reproduces them and does not adjust them, except where a sentence says it compares dollar figures after inflation. They describe the whole place, not any one building or street, and are not an appraisal, a rent determination, a tax bill, a safety rating or legal advice.