Tazewell County, IL Accessory Structures: ADU Owner Occupancy (2026)

055 permits an accessory dwelling on any residential or agriculture-zoned lot only if the lot's principal use is a single-family dwelling (A) and no more than one accessory dwelling sits on the lot (B). Clause (C) ties ownership directly to occupancy: the accessory dwelling shall be owned by the same person who occupies the habitable principal dwelling. That means an investor who does not live in the main house cannot add a second, separately owned unit on the same lot and call it an accessory dwelling; ownership of both structures has to sit with the resident of the principal home.

The accessory unit must also share the principal dwelling's driveway (D), and it is capped at 50% of the principal dwelling's floor area, with a floor area between 350 and 800 square feet (E). If the unit sits inside the principal dwelling and has its own separate entrance, that entrance cannot face any street the lot fronts (F), though a detached version is allowed inside an unattached garage for the principal dwelling's own residents (G). Every accessory dwelling also needs its own 911 address (I). These conditions were added by Ordinance LU-17-14 in 2017 and amended by Ordinance LU-21-02 in 2021.