Evanston, IL Accessory Structures: Garage Conversions (2026)
Garage conversion rules in Evanston, IL, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.
Key Facts
- Conversion method allowed
- Alter existing structure into ADU
- Nonconforming garage rule
- Exempt from standard it fails
- Term for garage ADU
- 'Coach house' in city code
- Governing sections
- § 6-4-6-10(A) and (J)
Summary
Evanston lets homeowners convert an existing detached garage or accessory building into a coach-house ADU, and a converted structure that already fails a zoning standard is grandfathered rather than forced to conform.
(J)Alterations of Existing Structures: If a detached ADU is created from an existing detached accessory structure that does not meet one or more of the standards within Section 6-4-6, the structure is exempt from the standard(s) it does not meet. However, any alterations that would result in the structure becoming less conforming with those standards it does not meet are not allowed.(K)Ownership and Occupancy: There is no requirement that the property owner reside on the property, however, an ADU shall remain under common ownership with the residential building. Occupancy of the ADU shall be limited to no more than one (1) family. (Ord. No. 86-O-20, § 3, 9-29-2020)
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 21).
Full Breakdown
Evanston's zoning code specifically allows an accessory dwelling unit to be created by converting an existing structure, not just building new, the code even defines a 'coach house' as a detached ADU that includes a garage. Section 6-4-6-10(A) authorizes creating an ADU through alteration of an existing structure. Where the garage or accessory building being converted doesn't already meet current standards under Section 6-4-6 (yards, height, coverage), Section 6-4-6-10(J) exempts it from the standard(s) it fails, the nonconformity is grandfathered, but any alteration that makes it less conforming is prohibited. Converted ADUs are still capped at 1,000 square feet unless created purely by altering an existing structure at a single level.
Violations & Fines
Making a nonconforming garage conversion less conforming than it already is, for example expanding a setback encroachment, violates Section 6-4-6-10(J) and can be denied or ordered corrected by the City's Building & Development Services Division.
Frequently Asked Questions
Can I convert my detached garage into an ADU in Evanston?
What if my garage doesn't meet current setback or height rules?
Sources & Official References
Other rules in Evanston
Compare Evanston to another location·View the Illinois accessory structures overview
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Garage Conversions in Nearby Cities
How other cities in Cook County handle garage conversions.