ADU Pass
Nancy B Jefferson
ADU Pass helps homeowners in Nancy B Jefferson — a USPS locale inside Chicago, Cook County, Illinois — navigate the permit paperwork for building an accessory dwelling unit. This locale covers 1 ZIP code.
Chicago — city ADU rules and incentives
ADU legality: unclear
Illinois leaves ADU regulation to local municipalities under home-rule or Dillon-rule authority. Chicago permits ADUs subject to local conditions per its zoning ordinance.
City cost envelope
$194,025 all-in for a 525 sqft ADU (permit + build). Midpoint scenario.
Permit fee bundle: $2,400.
City viability (selected uses)
Cook County — county ADU rules and overlays
County ADU ordinance
Cook County, Illinois - the second-most-populous county in the United States with 5.1 million residents - regulates accessory dwelling units in unincorporated territory through the Cook County Zoning Ordinance, administered by the Cook County Department of Building and Zoning. Cook County's unincorporated footprint is small (roughly 2% of county land area) because the great majority of Cook is incorporated by Chicago and 134 suburban municipalities. Chicago's own ADU pilot ordinance (Chicago Municipal Code Sec. 17-9-0102) governs ADUs inside city limits in five designated pilot areas, which is where the bulk of Cook County ADU activity occurs. Suburban Cook municipalities (Evanston, Oak Park, Cicero, Schaumburg, Arlington Heights, Skokie, etc.) each set their own ADU rules under home-rule authority. Cook County's county-level ordinance is meaningful chiefly for the unincorporated pockets along the western and southern county boundaries.
State-floor overlay: Illinois has not enacted a statewide ADU preemption statute. Cook County and its 135 incorporated municipalities (Chicago plus 134 suburban) retain home-rule authority over ADU zoning. Illinois Constitution Art. VII grants home-rule powers to municipalities of population greater than 25,000.
County regulatory overlays
Cook County administers flood-hazard, and (where mapped) coastal, wildland-fire, historic, and airport overlays that shape ADU project feasibility. The most consistent overlay across the county is FEMA NFIP floodplain regulation; other overlays apply to specific geographies inside the county.
- FEMA NFIP Special Flood Hazard Areas in Cook County — A new ADU in a mapped SFHA must be elevated to or above the Base Flood Elevation; cost impact on the project is often material.
- Historic districts and individually-listed historic resources
County permitting (unincorporated parcels)
Cook County issues building permits for parcels in unincorporated territory through its development services / planning department, with separate review tracks for zoning conformance, building-code compliance, on-site sewage where applicable, floodplain compliance, and addressing. Inside incorporated municipalities, city departments handle their own permits; the county's authority is geographically limited to unincorporated territory. An ADU permit application is typically processed as a residential building permit with a zoning verification step against the county's ordinance for the parcel's zoning district.
Illinois state — ADU law and programs
State financing programs
Illinois does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. The Illinois Housing Development Authority (IHDA) is the state's housing finance agency and administers a robust portfolio of homebuyer products: Access Forgivable, Access Deferred, Access Repayable down-payment-assistance variants, the IHDA Mortgage first-mortgage product, and the federal Low-Income Housing Tax Credit allocation. The 2025 IHDA Access Home program offers DPA equal to 6% of purchase price up to $15,000. None target ADU construction directly; an ADU-bearing primary residence on an Illinois lot can qualify for the underlying mortgage when other criteria are met.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Code
- 60612
Post Office
- 116 S Western Ave, 60612