Kankakee County, IL Zoning Overlays & Bonuses: Density Bonus Law (2026)

000 unit per acre. The yield formula starts with the base site area, after subtracting rights-of-way and easements, multiplied by that base density to get the base number of lots. Section 117-126(g) then adds a 10 percent Conservation Design Bonus to that base lot count, and the planning director can add a further 5 percent bonus, at his discretion, "as an incentive for providing unique amenities or special features" such as fishing docks, trails, wildlife habitat improvements or created wetlands. In exchange, at least 50 percent of the gross site area must be permanently preserved as common open space, protected in perpetuity through a recorded conservation easement, a governmental entity's restrictive covenant, or an equivalent instrument approved by the state's attorney; unusually large wetlands or floodplain acreage can push that set-aside above 50 percent.

Conservation design lots are expressly exempt from the zoning ordinance's standard lot area, lot width, lot coverage and setback rules, though lots within 150 feet of an existing subdivision cannot be smaller than 80 percent of that subdivision's average lot size. If a property owners' association will own and maintain the open space, § 117-126(i)(5) requires mandatory membership, lien authority to collect dues, and a special service area under 35 ILCS 200/27-5 as a funding backstop.