How old are the homes in South Wilmington, IL?

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

75.9% (±15.0 points) of the homes in South Wilmington, IL were built before 1980 (2020–2024 American Community Survey).

29.7% were built before 1940.

1.1% were built in 2010 or later.

Figures last updated on November 12, 2026.

Built before 1980: 75.9% (±15.0 points)
Built before 1940: 29.7%
Built 2010 or later: 1.1%

When the homes in South Wilmington were built

Housing units by year structure built, 2020–2024
Year built	South Wilmington	Grundy County	Illinois	United States
2020 or later	1.1% (±1.5 points)	1.8%	0.7%	2.0%
2010 to 2019	0.0% (±12.4 points)	9.4%	5.0%	9.4%
2000 to 2009	9.9% (±4.2 points)	24.8%	11.2%	13.6%
1990 to 1999	7.8% (±3.7 points)	14.2%	10.5%	12.4%
1980 to 1989	5.3% (±4.2 points)	8.4%	9.2%	12.9%
1970 to 1979	4.2% (±2.7 points)	15.1%	14.2%	14.2%
1960 to 1969	19.8% (±8.1 points)	6.0%	11.5%	9.9%
1950 to 1959	13.4% (±6.0 points)	5.6%	11.9%	9.5%
1940 to 1949	8.8% (±5.0 points)	3.5%	5.6%	4.4%
1939 or earlier	29.7% (±9.5 points)	11.2%	20.2%	11.7%

In South Wilmington, the share of homes built before 1980 is higher than in Grundy County (41.4%).

It is not measurably different from Illinois (63.4%).

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

In Grundy County, South Wilmington ranks 4 of 29 places with a published estimate, from highest to lowest share of homes built before 1980.

Statewide, it ranks 1044 of 2,751.

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 (71.7%) and the share built before 1980 (75.9%).

Homes built before 1980 in places near South Wilmington

Nearest places with a published estimate, compared with South Wilmington
Place	Distance	Homes built before 1980	Compared with this place
South Wilmington	—	75.9% (±15.0 points)	—
East Brooklyn	0.7 mi	66.6% (±33.0 points)	Not measurably different
Greenfield Township	1.8 mi	63.4% (±12.7 points)	Not measurably different
Gardner	2.2 mi	75.1% (±12.6 points)	Not measurably different
Garfield Township	3.1 mi	72.6% (±11.9 points)	Not measurably different
Braceville	3.6 mi	68.6% (±16.4 points)	Not measurably different
Essex	4.6 mi	45.4% (±14.0 points)	Lower
Braceville Township	4.8 mi	35.9% (±7.2 points)	Lower
Godley	5.2 mi	11.3% (±6.6 points)	Lower

Nearby places with a measurably lower figure: Essex, IL (45.4%), Braceville Township, IL (35.9%), Godley, IL (11.3%).

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

Homes built before 1980 across Grundy County, place by place

Rank	Place	Homes built before 1980
1	Kinsman	89.6% (±56.5 points)
2	Goodfarm Township	81.3% (±59.3 points)
3	Verona	76.1% (±23.2 points)
4	South Wilmington	75.9% (±15.0 points)
5	Gardner	75.1% (±12.6 points)
6	Garfield Township	72.6% (±11.9 points)
7	Vienna Township	72.4% (±18.3 points)
8	Morris Township	70.7% (±10.4 points)
9	Braceville	68.6% (±16.4 points)
10	East Brooklyn	66.6% (±33.0 points)

Showing 10 of 29 places in Grundy County, ranked from highest to lowest.

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 South Wilmington

How old are most homes in South Wilmington?

75.9% of homes in South Wilmington, IL were built before 1980 (2020–2024 American Community Survey).

Do homes in South Wilmington 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 71.7% and 75.9% of homes in South Wilmington were built before then.

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

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 — South Wilmington village, Illinois

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 South Wilmington village, Illinois (place:71370, in state:17).

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.