Accessory Structures in Evanston, IL

If you live in Evanston or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Evanston has 5 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

ADU Rules

Evanston allows one accessory dwelling unit per zoning lot, attached, internal, or detached, capped at 1,000 square feet for new construction, with no minimum lot size or owner-occupancy requirement.

Key details: Units allowed: 1 ADU per zoning lot. Minimum lot size: None required. New-construction size cap: 1,000 sq ft maximum. Owner-occupancy: Not required. Off-street parking: None required for the ADU.

Building an ADU that exceeds the size cap, adds a second accessory unit on the lot, or skips zoning approval is a violation; noncompliance can draw a $100 to $1,000 per day fine under § 6-3-10-5.

Shed & Carport Rules

Evanston allows garden sheds in residential rear yards but bans housing birds, poultry (other than hens), or livestock in them, and caps detached accessory coverage at 40% of the rear yard.

Key details: Min. distance from principal building: 10 feet. Min. setback from property line: 3 feet (residential rear/side). Max. rear-yard coverage: 40% of rear yard. Max. height (flat/mansard roof): 14.5 feet.

Erecting a shed without a certificate of zoning compliance, or one exceeding the height or rear-yard coverage limits, is enforced by the Zoning Administrator, who can deny or revoke the compliance certificate.

Tiny Homes

Evanston has adopted Appendix AQ, Tiny Houses, of the 2021 International Residential Code by name under City Code Section 4-9-2, giving tiny houses their own construction standard.

Key details: Adopted appendix: IRC Appendix AQ, Tiny Houses. Base code: 2021 International Residential Code. Adoption authority: § 4-9-2, Amendments. Enforcing agency: Building & Development Services Division.

Residential Code violations, including noncompliant tiny house construction, are fined $150 first offense, $400 second, $750 third and beyond under Section 4-9-3, with each day a separate violation.

Garage Conversions

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.

Key details: 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).

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.

ADU Owner Occupancy

Evanston does not require the property owner to live on-site to have an accessory dwelling unit, but the ADU must stay under common ownership with the main house and house no more than one family.

Key details: Owner occupancy required?: No. Ownership rule: Common ownership with main house. Occupancy limit: One family maximum. Governing section: Evanston City Code § 6-4-6-10(K).

No fine is listed for occupancy alone, but occupying an ADU without common ownership or beyond the one-family limit is a zoning violation enforceable by the City's Building & Development Services Division.

The Bottom Line

Evanston's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Evanston is broadly strict or permissive.

All of the above reflects Evanston's municipal code as of our last review. If you need specifics on fines, exemptions, or filing requirements, the detailed ordinance pages linked above have the full breakdown.