How old are the homes in Boulder, MT?

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

70.8% (±17.8 points) of the homes in Boulder, MT were built before 1980 (2020–2024 American Community Survey).

18.5% were built before 1940.

2.9% were built in 2010 or later.

Figures last updated on November 12, 2026.

Built before 1980: 70.8% (±17.8 points)
Built before 1940: 18.5%
Built 2010 or later: 2.9%

When the homes in Boulder were built

Housing units by year structure built, 2020–2024
Year built	Boulder	Jefferson County	Montana	United States
2020 or later	0.0% (±5.3 points)	3.4%	2.3%	2.0%
2010 to 2019	2.9% (±3.6 points)	10.6%	11.7%	9.4%
2000 to 2009	12.3% (±7.4 points)	16.6%	14.0%	13.6%
1990 to 1999	3.4% (±4.6 points)	20.1%	12.3%	12.4%
1980 to 1989	10.5% (±7.4 points)	8.7%	10.7%	12.9%
1970 to 1979	22.6% (±9.5 points)	19.4%	16.0%	14.2%
1960 to 1969	14.7% (±8.3 points)	4.7%	7.4%	9.9%
1950 to 1959	10.7% (±7.6 points)	4.6%	8.3%	9.5%
1940 to 1949	4.3% (±4.5 points)	1.8%	4.5%	4.4%
1939 or earlier	18.5% (±9.0 points)	10.1%	12.8%	11.7%

In Boulder, the share of homes built before 1980 is higher than in Jefferson County (40.6%).

It is also higher than in Montana (49.0%).

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

In Jefferson County, Boulder ranks 2 of 4 places with a published estimate, from highest to lowest share of homes built before 1980.

Statewide, it ranks 60 of 167.

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 (48.2%) and the share built before 1980 (70.8%).

Homes built before 1980 in places near Boulder

Nearest places with a published estimate, compared with Boulder
Place	Distance	Homes built before 1980	Compared with this place
Boulder	—	70.8% (±17.8 points)	—
Clancy	16 mi	28.0% (±12.1 points)	Lower
Montana City	22 mi	22.7% (±7.2 points)	Lower
Walkerville	24 mi	87.9% (±14.0 points)	Not measurably different
Helena West Side	25 mi	55.3% (±22.3 points)	Not measurably different
Whitehall	25 mi	75.6% (±18.9 points)	Not measurably different
Helena	25 mi	58.4% (±4.0 points)	Not measurably different
East Helena	26 mi	67.9% (±20.3 points)	Not measurably different
Helena Valley Southeast	29 mi	28.5% (±7.2 points)	Lower

Nearby places with a measurably lower figure: Clancy, MT (28.0%), Montana City, MT (22.7%), Helena Valley Southeast, MT (28.5%).

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

Homes built before 1980 across Jefferson County, place by place

Rank	Place	Homes built before 1980
1	Whitehall	75.6% (±18.9 points)
2	Boulder	70.8% (±17.8 points)
3	Clancy	28.0% (±12.1 points)
4	Montana City	22.7% (±7.2 points)

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 Boulder

How old are most homes in Boulder?

70.8% of homes in Boulder, MT were built before 1980 (2020–2024 American Community Survey).

Do homes in Boulder 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 48.2% and 70.8% of homes in Boulder were built before then.

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

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 — Boulder city, Montana

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 Boulder city, Montana (place:08575, in state:30).

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.