Mayor Lori E. Lightfoot today introduced an innovative ordinance to expand housing access to thousands of residents across Chicago by permitting accessory dwelling units, also known as additional dwelling units (ADU), such as attics, basements, and coach houses, to become moderate-cost rental units. Following decades of policy decisions that limited their construction, the proposed ordinance would amend the City’s Municipal Code to lawfully permit ADUs in buildings, ensuring more equitable access to housing options across Chicago’s communities and providing financial stability for homeowners with existing ADUs.

“The City needs to be creative and realistic about how and where we can increase affordable housing opportunities for renters while also helping property owners deal with the financial demands of their buildings,” said Mayor Lightfoot. “With this sustainable and cost-effective approach, we are providing residents with more equitable access to affordable housing options citywide.”

Recommended for legalization by the Mayor’s Transition Committee and in the Department of Housing’s (DOH) “One Chicago” five-year housing plan, ADUs will increase the supply of available housing for renters and create new financial opportunities for Chicago building owners and homeowners, including seniors who will be able to use the added income from an ADU to remain in their homes. In addition, by legalizing housing options that are already part of the fabric of the city’s neighborhoods, the ordinance will also allow for “gentle” density that will not be visible from the street and thus will fit within the existing neighborhood character.

“The ordinance is an almost invisible way to increase rental options,” said DOH Commissioner Marisa Novara. “Legalizing ADUs can have a real and positive impact on homeowners needing extra income to cover rising property taxes or adapting to age in place. For renters, they also provide a lower-cost option than other units, especially due to our partnership with the Low-Income Housing Trust Fund.”

Developed in partnership by the Departments of Housing (DOH), Planning and Development (DPD), and Buildings (DOB) with input from an advisory group assembled by the Urban Land Institute’s Chicago chapter, the proposed zoning code changes would define new living spaces within attics and basements as “conversion units” and spaces in accessory structures as “coach house units.” The code would also allow at least one ADU per building in all residential zoning districts, however ADUs proposed for buildings in select single-family districts (RS1, RS2) would require a special use permit from the Zoning Board of Appeals.

“Chicago faces the important need of creating more housing units that are affordable to residents in each neighborhood,” said Ald. Harry Osterman (48th Ward), chairman of the City Council Housing and Real Estate committee. “This ordinance enables property owners to create accessory dwelling units in a streamlined process that will add to our affordable housing stock and benefit many Chicagoans.”

ADU construction was largely prohibited in Chicago starting in 1957 with the introduction of minimum lot area and parking requirements to the City’s zoning code, along with a prohibition of secondary residential structures on single lots. Ongoing downzoning efforts in residential areas have further reduced opportunities to add units to existing buildings.

“AARP Illinois commends the Lightfoot administration for its efforts to increase housing options in Chicago,” said Mary Anderson, Chicago Director of AARP Illinois. “Ensuring that older adults have affordable and accessible housing is a high priority for our organization, and ADUs are a prime example of housing that would allow older adults to age in place.”

"This is a watershed improvement to the zoning code that will resonate citywide," said DPD Commissioner Maurice Cox. "In ways both big and small, the additional units created through this ordinance will support the needs of property owners, renters and even neighborhood businesses that depend on the patronage of local residents."

“The REALTORS® commend the efforts of the City. Solving the affordable housing crisis requires new and pragmatic solutions,” said Kristopher J. Anderson of the Chicago Association of REALTORS®. “Through this measure, the City is taking initial steps to maximize dwelling space and allow homeowners and housing providers to re-invest in their buildings. This will spur growth in construction and trades and produce increased tax revenue.”

Chicago currently has an unknown number of existing non-conforming coach houses and basement and attic apartments that are in varying states of compliance with City regulations. In addition to allowing new construction, the proposed ordinance is intended to bring those existing modifications into legal, compliant states. Existing ADUs that were constructed without zoning changes or building permits would be allowed to become compliant without penalty through a new permitting and inspection process.

Many existing ADU units are only illegal due to outdated zoning rules. Providing a pathway to legalization helps preserve thousands of existing units for the families that already live there.

“The Department of Buildings works each day to help ensure the city’s housing stock is safe and livable,” DOB Commissioner Judith Frydland said. “Too often, I’ve encountered landlords who avoided applying for a permit or tenants who were afraid to complain about unsafe conditions because the zoning status of their apartment was unclear. I am excited we have found a solution that will bring these homes into compliance with City codes.”

This measure is part of the City’s larger efforts to address housing issues across the City and especially during the coronavirus 2019 (COVID-19) pandemic. For more information and updates on COVID-19, text COVID19 to 78015, email coronavirus@chicago.gov or visit Chicago.gov/coronavirus.

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