RS-3 Residential Single-Unit (Detached House) District A Chicago zoning district · Title 17
Detached single-family houses on individual lots. RS districts are the city's lowest-density residential zones; density (minimum lot area per unit) and required yards tighten as the dash number drops.
Example on a 25 × 125 ft lot. The dashed box is the maximum zoning envelope, the buildable footprint after setbacks, raised to the 30 ft height limit. The solid building is an illustrative example at FAR 0.9: covering the full footprint reaches only ~2 stories before the floor-area cap binds, so a taller building needs a smaller floor plate. Residential floors sit over a partially above-grade basement, which counts toward height but not floor area. Front yard is context-dependent (average of adjacent lots); actual varies.
Specifications
- Zoning Ordinance reference
- §17-2-0100
View in the Chicago Zoning Ordinance - Floor area ratio (FAR)
- 0.9Ground floor Type A (accessible) units, except in a detached house, are not counted as floor area. That is an exemption, not a higher ratio: it is worth whatever those units occupy, on top of this FAR — §17-2-0304-D
- Maximum building height
- 30 ft, measured to the top floor's ceiling (flat roof) or mean roof height (pitched roof). §17-17-0311.
- Lot area per unit (density)
- 2,500 sq ft of lot area per dwelling unit.Ground floor Type A (accessible) units, except in a detached house, are left out of this calculation, so each one is a unit above what the lot area alone allows — §17-2-0303-B(2)
- Minimum lot area
- 2,500 sq ft
- Rear yard open space
- The greater of 225 sq ft per unit or 6.5% of lot area, containing a circle at least 15 ft in diameter. Must sit in the rear yard, at or within 4 ft of grade. §17-2-0307.
- On-site open space
- —
- Parking requirements
- 2 spaces per unit for detached houses; 1.5 spaces per unit for two-flats. Lots 33 ft wide or less are exempt. §17-10-0207-A.
Setbacks
- Front yard
- Average of the front yards of the nearest two lots on each side; vacant lots assumed at 20 ft (16% of depth). §17-2-0305.
- Side yard
- Combined at least 20% of lot width; each side at least 2 ft or 8% of width. §17-2-0309.
- Rear yard
- The lesser of 50 ft or 30% of lot depth; 28% for a detached house; 24% for a building of no more than 19 units in which at least 33% of the units are accessible. §17-2-0306.
Allowed Uses
Curated from the §17-2-0207 use table. P = permitted by-right; S = special-use approval required. Always confirm against the full ordinance text.
- Detached house
- Two-flat (RS3 only)
- Conversion unit & coach house (RS3 by-right)
- Family community home
- Day care
- Schools
- Religious assembly
- Parks & recreation; community gardens
- Cultural exhibits & libraries
- Fire stations & minor utilities
- Vacation rental / shared housing unit
- Community home (group)
- Domestic violence residence
- Transitional residences & shelters (RS3)
- Temporary overnight shelter (RS3)
- Community / recreation centers
- Police station
- Major utilities & services
- Freestanding wireless towers
In Chicago, RS-3 allows a floor area ratio of 0.9 and a minimum lot area of 2,500 sq ft, with a height limit of 30 ft. The figures above are the RS-3 standards as the Chicago Zoning Ordinance states them, each citation linking to the section it comes from in our hosted copy of Title 17. What a specific lot allows also depends on its frontage, depth, corner or through geometry, and any overlay it sits in — run the RS-3 numbers for your lot to see those applied.
Reference figures are modeled from the Chicago Zoning Ordinance (Title 17) for general guidance and do not constitute zoning or legal advice. Lot-specific limits depend on frontage, depth, adjacencies and overlays — analyze a specific address for exact figures. Always confirm against the official ordinance.