Chicago, IL Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- RS1 / RS2 minimum
- 400 sq ft/unit or 6.5% of lot
- RS3 minimum
- 225 sq ft/unit or 6.5% of lot
- RT4 minimum
- 65 sq ft/unit or 6.5% of lot
- RM5 minimum
- 36 sq ft/unit or 5.25% of lot
- Parking areas
- Cannot count toward open space
Summary
In RS, RT, RM4.5 and RM5 districts, Chicago requires 6.5% of lot area (or more per dwelling unit) kept open in the rear yard, effectively capping how much of the lot buildings can cover.
17-2-0307 Rear Yard Open Space. All development in RS, RT, RM4.5 and RM5 districts is subject to the following minimum rear yard open space standards, except as expressly allowed under the townhouse development standards of Section 17-2-0500. ... RS1 400/6.5 ... RS3 225/6.5 ... RT4 65/6.5 ... RM5 36/5.25
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-74: Current through Council Journal of June 17, 2026).
Full Breakdown
Chicago's zoning code doesn't set a flat maximum lot-coverage percentage: it works backward, mandating how much rear yard must stay open. In RS1 and RS2 districts, 400 square feet per dwelling unit or 6.5% of lot area (whichever is larger) must remain unbuilt in the rear yard; RS3 drops to 225 sq ft/6.5%, RT3.5 to 100 sq ft/6.5%, RT4 to 65 sq ft/6.5%, RM4.5 to 50 sq ft/6.5%, and RM5 to 36 sq ft/5.25%. The open area must sit at ground level, be substantially covered in grass, ground cover, shrubs, plants, trees or usable outdoor features, and be large enough to fit a circle 10 to 20 feet in diameter depending on district. Driveways and off-street parking pads don't count toward it.
Violations & Fines
New construction and additions that don't meet the minimum are rejected at zoning permit review by the Department of Buildings; noncompliant work requires a Zoning Board of Appeals variance or administrative adjustment to proceed.
Frequently Asked Questions
Does Chicago cap lot coverage with a flat percentage?
Can a driveway or parking pad count toward the required open space?
Sources & Official References
Other rules in Chicago
Compare Chicago to another location·View the Illinois building setbacks & zoning overview
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Lot Coverage Limits in Nearby Cities
How other cities in Cook County handle lot coverage limits.