Additional dwelling units.
Municipal Code of Chicago § 2-44-106
in effect2-44-106 Additional dwelling units.
(a) Title. This section shall be known and cited as the “Additional Dwelling Unit Ordinance”.
(b) Purpose. This section establishes affordability requirements for certain ADUs established in conformity with the Chicago Zoning Ordinance, Title 17 of the Municipal Code of Chicago, in order to preserve and expand available affordable housing in the City.
(c) Definitions. As used in this section:
“Additional Dwelling Unit” or “ADU” means a coach house, as defined in Section 17-17-0234.6, or a conversion unit, as defined in Section 17-17-0240.6.
“Affordable ADU” means any one or more affordable housing units designated as such and required to be registered as such by the Department of Housing pursuant to subsection (e) of this section.
“Affordable housing unit” means housing that is affordable to and, if occupied, rented to households earning up to 60% of the area medium income (“AMI”), as published annually by the Department of Housing. As used in this definition: “affordable” means annual rent less than or equal to the amount at which total monthly housing costs, as specified in rules duly promulgated by the Commissioner, do not exceed 30% of income for a household making 60% of the area median income.
“Area median income” or “AMI” means the median household income for the Chicago Primary Metropolitan Statistical Area, as calculated and adjusted on an annual basis by the United States Department of Housing and Urban Development.
“Commissioner” means the Commissioner of Housing.
“Owner” has the meaning ascribed to the term “property owner” in Section 17-17-02134.
“Residential building” means a residential building, as defined in Section 17-17-02146, that is a principal building, as defined in Section 17-17-02125.
(d) Affordable ADUs – Required when. If, pursuant to Sections 17-2-0303-C, 17-3-0308, or 17-9-0201-F, two or more ADUs are added, either separately or in any combination, at any time after May 1, 2021, to a residential building other than to a residential building owned, operated or maintained by the Chicago Housing Authority, the owner of such building shall maintain 50% of those newly added ADUs as affordable housing units for the duration of the affordability requirement as set forth in subsection (i) of this section; provided, however, that if this 50% calculation results in a fractional number, any such fractional result shall be rounded down to the nearest integer. This subsection (d) shall run with the land and be enforceable against any subsequent owner.
(e) Registration. Prior to the application by a building owner for a building permit with the Department of Buildings for an ADU, the Department of Housing will advise the owner whether any of the proposed ADUs are required to be maintained as affordable housing units. If the owner is required under this section to maintain any of the proposed ADUs as affordable housing units, the owner shall register those designated Affordable ADUs with the Department of Housing in accordance with rules duly promulgated by the Commissioner. Such registration shall be accompanied by the Affordable ADU Initial Registration Fee for each Affordable ADU, as set forth in Section 2-44-065, to defray the costs of administering this section.
(f) Recorded notice – Required. For each Affordable ADU, the Department of Housing shall require the owner to record, with the Cook County Recorder of Deeds, a document in a form prescribed by the Commissioner, against the property on which such Affordable ADU is located indicating that such Affordable ADU is required to be maintained as an affordable housing unit for the duration of the affordability requirement, as set forth in subsection (i) of this section. Such notice shall require owners and subsequent owners to keep owner contact information, including an e-mail address, current with the Department of Housing.
(g) Building permit – Prohibited when. No building permit shall be issued by the Department of Buildings for any ADU unless the Department of Housing certifies, i.e. pre-certifies, that:
(1) The application for any pre-certification located in an RS zoning district complies with all requirements established in Section 17-7-0570.
(2) The applicant for such pre-certification has provided the Department a copy of any recorded notice required under subsection (f) of this section.
(3) The Department has provided notice of the application to the local alderman. Such notice shall include the street address of the existing building and the name and mailing address of the applicant.
(4) The applicant for a permit to build a coach house, as defined in Section 17-17-0234.6, has committed and agreed to obligate the general contractor, and any subcontractors retained, to participate in Registered Apprenticeship Programs which are approved by and registered with the United States Department of Labor’s Office of Apprenticeship, or its successor organization, for the trades that will perform work under the permit.
(h) Annual compliance affidavit – Required. Each owner of one or more Affordable ADUs shall, on schedule to be determined by the Commissioner each calendar year following initial registration of such Affordable ADUs with the Department of Housing, file an annual compliance affidavit with the Department of Housing certifying that each such Affordable ADU is being maintained as an affordable housing unit within the meaning of this section.
(i) Duration of affordability requirement. Each Affordable ADU shall be maintained as an affordable housing unit for 30 years from the date of the recorded notice required under subsection (f) of this section.
(j) Inapplicability of other affordability requirements. Affordable ADUs required under this section to be maintained as affordable housing units shall be exempt from Sections 2-44-070, 2-44-080, 2-44-090, 2-44-100 and 2-44-105.
(k) Rules. The Commissioner is authorized to adopt such rules as the Commissioner deems necessary or appropriate for the proper implementation, administration and enforcement of this section.
(l) Penalty. In addition to any other penalty provided by law, any owner of an Affordable ADU who violates this section shall be subject to a fine of $500.00 for each offense. Each day that a violation continues shall constitute a separate and distinct offense.
(m) Private right of action. An aggrieved tenant may enforce this section against any owner subject to this section by means of a civil action in which the court may provide injunctive relief or award treble damages and the plaintiffs court costs and reasonable attorney fees.
(n) Chicago Low-Income Housing Trust Fund. The Commissioner is authorized to enter into agreements with the Chicago Low-Income Housing Trust Fund to reserve City-funded vouchers for use in connection with Additional Dwelling Units.
(o) Low- and moderate-income household assistance. The Commissioner is authorized to establish grant programs to assist low- and moderate-income households, or property owners who commit to developing Additional Dwelling Units for low- and moderate-income households, with the construction or rehabilitation of Additional Dwelling Units (including modifications that enhance accessibility for people with disabilities).
(p) Annual reporting requirement. By March 31 of each year beginning in 2027, the Department will issue a report to the Committee on Zoning, Landmarks and Building Standards detailing the number and distribution of ADUs pre-certified by the Department and building permits issued as a result of those pre-certifications by the Department of Buildings during the prior calendar year.
(Added Coun. J. 12-16-20, p. 26066, § 3; Amend Coun. J. 9-25-26, p. 32815, § 2)
Source: City of Chicago, Municipal Code of Chicago (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/chicago/latest/chicago_il/0-0-0-2599220Fetched: 10/24/2026