Accessory Structures in Will County, IL (2026)

3 rules for unincorporated Will County, Illinois.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Will County. If you live within an incorporated city, that city's own rules apply: see the city list below.

ADU Rules

Unincorporated Will County allows one accessory dwelling unit per lot with detached houses, capped at 650 square feet or 49% of the main home's floor area.

Will County ADU Zoning Rules

Some Restrictions

Will County Code § 155-10.10(C)

(h) Size. The floor area of an ADU may not exceed 49% of the gross floor area of the principal dwelling unit on the subject lot (excluding any attached garage), or 650 square feet, whichever is less. (d) Owner occupancy. The owner of record must reside in either the principal or accessory dwelling unit for a minimum of six months of each calendar year.

Full ordinance details →Official source ↗

ADU Owner Occupancy

Will County requires the property owner to live in either the main house or the accessory dwelling unit at least six months a year, on unincorporated land only.

Will County ADU Owner-Occupancy Rule

Some Restrictions

Will County Code § 155-10.10(C)(2)(d)

Owner occupancy. The owner of record must reside in either the principal or accessory dwelling unit for a minimum of six months of each calendar year. (e) Methods of creation. An accessory dwelling unit may be created through any of the following methods: 1. Converting existing area within the interior of a house (e.g., attic or basement) to an ADU; 2. Add...

Full ordinance details →Official source ↗

Shed & Carport Rules

Unincorporated Will County caps accessory buildings at 1,200-3,000 sq. ft. depending on district, allows a 5-foot rear setback, and requires a building permit even for the smallest sheds.

Will County Shed Size, Setback & Permit Rules

Some Restrictions

Will County Code § 155-3.30(B)

E-1 E-2 R-1 R-2 R-2A R-3 R-4 R-5 R-6 S4 Rear (Accessory Structures) 5 5 5 5 5 5 5 5 5 B2 Maximum Acc. Building Area (sq. ft.) 3,000 3,000 1,800 1,800 1,800 1,500 1,200 1,200 1,200 Accessory Buildings [height] 25 25 25 25 25 25 25 25 25

Full ordinance details →Official source ↗

All Will County ordinances

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