DuPage County, IL Building Setbacks & Zoning: Setback Rules (2026)
Key Facts
- Front yard (R-1 single-family)
- 40 feet minimum
- Interior/corner side yard
- 20 ft interior, 40 ft corner side
- Rear yard
- 50 feet minimum
- Base height
- 36 ft, up to 72 ft with yard increase
- Floor area ratio
- .20 for single-family dwellings
- HOA deck/patio exception
- 3 feet from rear lot line
- Fine for violation
- $100-$500 per week (Sec. 37-1417)
Summary
Unincorporated DuPage County's R-1 single-family district requires a 40-foot front yard, 20-foot interior side yards, a 40-foot corner side yard, and a 50-foot rear yard. Zoning Ordinance Sec. 37-701.4(A) sets those minimums alongside a 36-foot base height limit and a .20 floor area ratio for every principal building on the lot.
Notwithstanding section 37-700.4 of this chapter and except as otherwise provided herein, each principal building located in the R-1 district shall provide for one (1) front yard, two (2) interior side yards or one (1) interior side yard and one (1) corner side yard, and one (1) rear yard. ... A.Minimum Yard, Height, FAR and Lot Coverage Required: Use: Front Yard Interior Side Yard Corner Side Yard Rear Yard Height FAR Lot Coverage Single-family detached dwelling 40′ 20′ 40′ 50′ 36′, (except that where a lot size is 40,000 sq. ft. or more, the height of a building or attached structure may be increased 1′ for each 1′ all required yards are increased. The required yard increase shall be measured from the portion of the building or attached structure which exceeds the maximum height. In no case shall the height exceed 72′). .20 NA
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).
Full Breakdown
4 sets the yard, height, and floor area ratio table for the R-1 single-family district, and every principal building must provide one front yard, two interior side yards, or one interior and one corner side yard, and one rear yard under the section's opening sentence. 20 floor area ratio. The height limit is not absolute: on a lot of 40,000 square feet or more, the building may rise one additional foot for every foot all required yards are increased, measured from the part of the structure that exceeds 36 feet, up to an outer ceiling of 72 feet.
Schools, places of assembly, libraries, museums, and art galleries use the same yard minimums but add a 50 percent lot coverage cap and a larger 40-foot side yard where the lot is adjacent to a residential zoning district, dropping to 20 feet next to non-residential zoning. Subsection A also carves out two narrow accessory-structure exceptions inside planned developments with an active Homeowners Association: decks, gazebos, patios, and terraces may sit as close as 3 feet from the rear lot line where the HOA has voted to allow the encroachment and files written authorization with the County building permit application, and docks may extend up to 10 feet into a private lake in common open space under the same HOA-approval process. 7 and 37-1411.
Violations & Fines
Building or maintaining a structure that encroaches into the required front, side, or rear yard, or that exceeds the height or floor area ratio limits in Section 37-701.4, is enforced under Section 37-1417. The zoning official issues a notice of violation giving the owner fourteen days to correct the encroachment or request an administrative appeal; an uncorrected violation carries a fine of $100 to $500, with each week counted as a separate offense, plus court costs.
Frequently Asked Questions
How close to my property line can I build in DuPage County's R-1 district?
Can I build higher than 36 feet in the R-1 district?
Can my deck or patio sit closer to the rear lot line than 50 feet?
Sources & Official References
Other rules in DuPage County
Compare DuPage County to another location·View the Illinois building setbacks & zoning overview
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