Chicago ADU permit requirements
Last reviewed: June 22, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Chicago, Illinois means pulling a building permit from the local authority that issues it. ArchPermit tracks 14 source-cited requirements (5 required, the rest conditional) for this jurisdiction. Submittals go through DOH EFORMS (pre-cert) → DOB E-Plan / ProjectDox. These requirements were last reviewed June 22, 2026; confirm the exact forms and fees with the local permitting authority.
A source-cited checklist of what an ADU (accessory dwelling unit) permit package needs in City of Chicago. Every item links to its authoritative source; items that vary are flagged to confirm locally.
An ADU is a two-step approval: DOH issues a Pre-Certification Approval Letter (confirms zoning/eligibility — a building must be ≥20 years old for a conversion unit; one coach house is allowed regardless of age), and that letter must be included in the DOB plan-based building permit. ADUs are by-right in multi-unit/mixed-use and certain commercial districts citywide; in single-family RS districts only inside designated 'ADU-Allowed RS Areas' (§17-7-0754), which can carry annual per-block caps and owner-occupancy. Adding two or more ADUs requires 50% (rounded down) to be deed-restricted affordable for 30 years at ≤60% AMI. The 2025 expansion ordinance broadened ADUs beyond the original 5 pilot areas.
- ADU Pre-Certification Application (DOH, via EFORMS)required
Online DOH application capturing applicant, address, ownership/occupancy, existing legal units, year built, and ADU type(s)/count; auto-notifies the alderperson.
source · reviewed 2026-06-22 - ADU Pre-Certification Approval Letterrequired
DOH-issued approval letter generated after staff review; must be included in the DOB building-permit application (a pre-cert does not guarantee a permit).
source · reviewed 2026-06-22 - Architectural Plans (IL-licensed architect / structural engineer)required
Stamped construction drawings designed to the 2019 Chicago Construction/Rehabilitation Codes and Zoning Ordinance, uploaded to ProjectDox; only an IL-licensed architect/engineer or city-licensed expediter can file a plan-based permit.
source · reviewed 2026-06-22 - Building Permit Application (Form 400)required
The permit application uploaded to ProjectDox; its address, PINs, cost, description, area, height, and zoning must match the Dynamic Portal entries.
source · reviewed 2026-06-22 - Code Compliance / Zoning Matrix on Drawingsrequired
A matrix showing compliance with the 2019 Chicago Construction Codes and Chicago Zoning Ordinance, incorporated into the permit drawings.
source · reviewed 2026-06-22 - ADU Affordability Covenant (recorded)conditional
Required when adding 2+ ADUs — a 30-year covenant restricting the affordable unit(s) to ≤60% AMI, recorded with the Cook County Clerk.
source · reviewed 2026-06-22 - Administrative Adjustment (DPD)conditional
Where an ADU-Allowed RS Area requires it, obtain a DPD administrative adjustment (separate process, $500 fee) before establishing the ADU.
source · reviewed 2026-06-22 - Affordable ADU Registration + $500/unit Feeconditional
For 2+ ADUs, the owner registers each designated affordable unit with DOH and pays a $500 initial registration fee per affordable ADU.
source · reviewed 2026-06-22 - Annual Affordability Compliance Affidavitconditional
Required with the affordability covenant (2+ ADUs); certifies affordable rent against the AMI table, submitted at pre-cert and renewed annually.
source · reviewed 2026-06-22 - Applicant Acting as General Contractor (Form 401GC)conditional
Filed when the owner-applicant acts as their own GC (permitted for owner-occupants of ≤6-unit, ≤3-story residential buildings).
source · reviewed 2026-06-22 - Energy Code Compliance Statement (Form 408R)conditional
Residential energy-code compliance statement, required for applicable scopes.
source · reviewed 2026-06-22 - Excavation Certification (Form 402)conditional
Required where the scope involves excavation — relevant to a detached coach house (new foundation).
source · reviewed 2026-06-22 - Proof of Owner-Occupancyconditional
Required only where an ADU-Allowed RS Area imposes owner-occupancy: government photo ID plus one of a property-tax bill, utility bill, recorded deed, mortgage statement, or homeowner's insurance declaration.
source · reviewed 2026-06-22 - Registered Apprenticeship Program (RAP) Commitment — coach houseconditionalverify locally
To build a coach house, the applicant must obligate the GC and all subcontractors to U.S. DOL-approved Registered Apprenticeship Programs (no specific form published yet).
source · reviewed 2026-06-22