SB4071 104TH GENERAL ASSEMBLY

LRB104 20887 RTM 34559 b

104TH GENERAL ASSEMBLY
State of Illinois
2025 and 2026
SB4071

Introduced 2/24/2026, by Sen. Robert F. Martwick

SYNOPSIS AS INTRODUCED:

65 ILCS 5/11-13-30 new

Amends the Illinois Municipal Code. Provides that, beginning January 1, 2027, each municipality shall, by ordinance, authorize the development of accessory dwelling units. Provides that each municipality shall permit accessory dwelling units in all zoning districts that permit single-family dwellings without additional requirements for lot size, setbacks, aesthetic requirements, design review requirements, frontage, space limitations, or other controls beyond those required for single-family dwelling units without an accessory dwelling unit. Provides that a municipality is not required to allow more than one accessory dwelling unit for any single-family dwelling. Provides that accessory dwelling units may be constructed at the same time as the principal dwelling unit. Provides that no municipality shall: (A) require additional automobile parking spaces for a property with an accessory dwelling unit beyond the requirements for a single-family dwelling unit without an accessory dwelling unit; (B) require the establishment of a familial relationship between the occupants of an accessory dwelling unit and the occupants of a principal dwelling unit; or (C) establish a minimum or maximum limit on (i) square footage of an accessory dwelling unit or (ii) the number of bedrooms of an accessory dwelling unit. Limits home rule powers.

A BILL FOR

AN ACT concerning local government.

Be it enacted by the People of the State of Illinois, represented in the General Assembly:

Section 5. The Illinois Municipal Code is amended by adding Section 11-13-30 as follows:

(65 ILCS 5/11-13-30 new)

Sec. 11-13-30. Accessory dwelling units.

(a) As used in this Section, "accessory dwelling unit" means a residential living unit that is located on a lot containing a single-family dwelling that provides independent living facilities for one or more persons, including provisions for sleeping, eating, cooking, and sanitation, on the same parcel of land as the principal dwelling unit it accompanies. "Accessory dwelling unit" includes a structure that is (i) separate from the primary dwelling unit or (ii) attached to the primary dwelling unit.

(b) Notwithstanding any law to the contrary, beginning January 1, 2027, each municipality shall, by ordinance, authorize the development of accessory dwelling units in compliance with this Section.

(1) Each municipality shall permit accessory dwelling units in all zoning districts that permit single-family dwellings without additional requirements for lot size, setbacks, aesthetic requirements, design review requirements, frontage, space limitations, or other controls beyond those required for single-family dwelling units without an accessory dwelling unit. An accessory dwelling unit may be constructed as a new structure or from an existing structure, including but not limited to attached or detached garages, attics, basements, and backyard cottages.

(2) A municipality is not required to allow more than one accessory dwelling unit for any single-family dwelling.

(3) Accessory dwelling units may be constructed at the same time as the principal dwelling unit.

(4) No municipality shall:

(A) require additional automobile parking spaces for a property with an accessory dwelling unit beyond the requirements for a single-family dwelling unit without an accessory dwelling unit;

(B) require the establishment of a familial relationship between the occupants of an accessory dwelling unit and the occupants of a principal dwelling unit; or

(C) establish a minimum or maximum limit on (i) square footage of an accessory dwelling unit or (ii) the number of bedrooms of an accessory dwelling unit.

(c) A home rule municipality may not regulate accessory dwelling units in a manner inconsistent with this Section. This Section is a limitation under subsection (i) of Section 6 of Article VII of the Illinois Constitution on the concurrent exercise by home rule units of powers and functions exercised by the State.