Building permits, zoning and land rules in Cook County, Illinois

Unincorporated Cook County requires a building permit application for work other than qualifying ordinary repairs, with supplemental requirements for electrical and plumbing work¹. Cook County has adopted building, residential, mechanical, energy, fire, existing-building, plumbing and electrical codes, with local or Illinois amendments¹⁰. Orland Park¹¹, Park Forest¹², Lemont¹³ handle their own building permits. Woodridge¹⁴, Homer Glen¹⁵, Crete¹⁶ extend into Cook County from neighboring counties and handle their own building permits. Municipal building and zoning authority does not generally transfer septic approval: CCDPH covers Cook County systems except the named village exceptions; confirm the county containing a cross-county parcel⁴.

The Cook County Department of Building and Zoning handles unincorporated building permits at 69 West Washington Street, Chicago, IL 60602; call 312-603-0500 or email info.bnz@cookcountyil.gov³. Building permit materials must be digital; application questions go to intake.bnz@cookcountyil.gov¹⁷. Required materials include the application, child-support declaration, contractor letters of intent, scope of work and additional new-construction documents¹. Electronic submissions require a $100 residential or $500 non-residential deposit, credited toward the final building permit fee rather than covering the full cost¹. Cook County publishes a separate Building and Zoning fee schedule¹⁸. Construction inspections are required; permit issuance provides inspector contacts and required inspection stages, and construction also requires spot and final grade surveys¹.

Cook County zoning applies to unincorporated parcels; use the county parcel search and property index number to identify the district². Orland Park¹⁹, Tinley Park²⁰, Park Forest²¹, Lemont²², Steger²³ set their own zoning. Woodridge²⁴, Homer Glen²⁵, Crete²⁶, University Park²⁷ extend into Cook County from neighboring counties and set their own zoning. Municipal building and zoning authority does not generally transfer septic approval: CCDPH covers Cook County systems except the named village exceptions; confirm the county containing a cross-county parcel⁴. In unincorporated residential districts, lot area depends on district, dwelling type and sewer or septic service; setbacks and coverage limits also vary^5,6. Single-family minimum dwelling sizes range from 720 to 1,000 square feet⁶. The residential summary lists single-family height limits of 2.5 stories or 35 feet and accessory-structure limits of 15 feet⁶. Unincorporated property under contract needs a zoning certificate before closing².

Cook County Department of Public Health approves private sewage disposal systems except in incorporated Barrington Hills, Inverness, Palos Park and South Barrington, which use their own state-approved septic ordinances⁴. For unincorporated new construction served by septic, submit CCDPH approval with the building permit application¹. The septic application calls for a completed application, seven plan sets, a soil report, applicable supporting documents and payment by check or money order⁴. Going without sewer service still requires an approved private sewage system⁴. Only about 0.9% of Cook County soils lack severe limitations for conventional drain fields, making a parcel-specific soil evaluation essential before choosing a design²⁸. Buying or selling a home with a well or septic system typically requires an evaluation; CCDPH asks for requests two to three weeks ahead⁴.

A parked RV cannot be used for living, sleeping or other occupancy on a residential zoning lot in unincorporated Cook County, and cannot connect to gas, water or sanitary sewer service⁵. The ordinance allows no more than two parked RVs on such a lot and prohibits using an RV as an accessory structure⁵. A proposed tiny home must account for single-family minimum dwelling sizes of 720 to 1,000 square feet by residential district⁶. We could not confirm a separate tiny-home occupancy rule or temporary private-land camping terms; ask the Cook County Zoning Administrator about the proposed home and any construction-period accommodation².

1. Confirm unincorporated jurisdiction and find the parcel’s zoning district through Cook County’s property-index-number search^2,3.
2. Compare the design with district lot-area, dwelling-size, setback, height and coverage rules^5,6.
3. Obtain CCDPH septic approval for septic-served new construction, and arrange any well application through CCDPH^1,9.
4. Assemble the building application and supporting documents, then submit digital materials and pay the $100 residential deposit toward the final fee^1,17.
5. Obtain the driveway permit and any township approval for a curb cut or apron replacement²⁹.
6. Follow the inspection stages supplied with the building permit and provide spot and final grade surveys¹.
7. Arrange the certificate of occupancy with Building and Zoning: Cook County requires the certificate for construction, occupancy, alterations and land-use changes within its jurisdiction³⁰.

Obtain the required zoning certificate before closing on unincorporated Cook County property². For subdivision plans, Cook County publishes a Subdivision Manual; ask Building and Zoning which approvals the proposed division needs^3,31. New, modified or sealed water wells need a permit before work starts; suburban Cook County applications go through CCDPH using IDPH forms^9,32. Every unincorporated driveway needs a permit, and new curb cuts or public-right-of-way apron replacements need the township Highway commissioner’s approval or waiver²⁹. Work in a Cook County highway right-of-way also needs a Transportation and Highways construction/maintenance permit; check the highway-jurisdiction map and apply two to three months ahead³³. State-highway access and regulated floodway work have separate Illinois authorization requirements^34,35. Cook County’s effective property-tax rate is about 2%, with a median annual bill of about $6,053²⁸.