Chicago Zoning Code & Development Rules
Data version: Q2 2026 · Last updated 2026-05-13
TL;DR. Chicago uses a conventional Euclidean zoning system defined in the Chicago Zoning Ordinance (Title 17) with Residential (RS, RT, RM), Business (B), Commercial (C), Downtown (D), and Manufacturing (M) districts. Chicago also makes extensive use of Planned Developments (PDs) and Transit-Oriented Development bonuses. The city's unique aldermanic prerogative system gives local council members significant influence over zoning. Buildability™ returns your exact zone, FAR, and development potential.
Chicago zoning districts
RS-3 (Single-Family): 2,500 sq ft minimum lot, 30 ft height, 0.9 FAR. RT-4 (Two-Flat): 38 ft height, 1.2 FAR, Chicago's classic two-flat building type. RM-5 (Multi-Unit): 50 ft height, 2.0 FAR, mid-rise apartments. B-3 (Community Shopping): ground-floor retail with residential above. D (Downtown): DX, DC, DS sub-districts allowing high-rise office, residential, and mixed-use. PD (Planned Development): custom-negotiated density requiring City Council approval.
Aldermanic prerogative and Planned Developments
Chicago's aldermanic prerogative is an informal tradition where the local alderman holds veto-like influence over zoning changes in their ward. Practically, most rezonings and Planned Developments cannot advance through City Council without the ward alderman's support. PDs allow custom density, height, and uses beyond base zoning but require full council approval. Most major Chicago developments use PD zoning.
TOD bonuses and ARO requirements
Transit-Oriented Development (TOD) bonuses provide increased FAR and reduced parking within 600 ft of CTA or Metra rail stations. The Affordable Requirements Ordinance (ARO) requires 10-20% affordable units for projects receiving city subsidies or zoning changes. Both programs significantly affect project economics. TOD is the primary driver of new development along the Blue, Red, and Green Lines.
Permit process
Department of Buildings (DOB) handles building permits through E-Plan portal. Department of Planning and Development (DPD) handles zoning approvals. Standard residential by-right: 4-8 weeks. Planned Developments: 6-18 months including City Council approval. Permit costs: $2,000-$10,000 residential, $25,000+ for commercial PDs. ADUs allowed since 2020 ordinance with coach houses and garden units.
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