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, and 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 house)conditionalverify 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
Chicago ADU permit questions
- Do I need a permit to build an ADU in Chicago?
- Yes. An accessory dwelling unit (ADU) in Chicago requires a building permit. ArchPermit tracks 14 cited requirements for this jurisdiction (5 required, the rest conditional). Always confirm the exact forms, fees, and code edition with the local permitting authority that issues the permit.
- What does an ADU permit package require in Chicago?
- Core required items include: ADU Pre-Certification Application (DOH, via EFORMS); ADU Pre-Certification Approval Letter; Architectural Plans (IL-licensed architect / structural engineer); Building Permit Application (Form 400); Code Compliance / Zoning Matrix on Drawings. Each requirement links to its authoritative source, and nothing is permit-ready until an independent licensed professional reviews and seals it.
- How are ADU permits submitted in Chicago?
- Chicago accepts permit submittals via DOH EFORMS (pre-cert) → DOB E-Plan / ProjectDox. ArchPermit prepares a draft package you can submit there after a licensed architect reviews and seals it.