Downers Grove, IL Accessory Structures: Shed Rules (2026)

Sheds in unincorporated DuPage County are governed as detached accessory buildings under the DuPage County Zoning Ordinance, Chapter 37, with rules set by single-family district: Sec. 37-701 (R-1), Sec. 37-702 (R-2), Sec. 37-703 (R-3), and Sec. 37-704 (R-4). A permit must be obtained from the DuPage County Building & Zoning Department through the Accela Citizen Access portal before construction begins. The application requires a scalable Illinois-licensed plat of survey showing the proposed shed location and distances to lot lines; a construction plan is required only if the shed exceeds 150 sq. ft. The maximum detached accessory building size is 1,000 sq. ft. on lots up to 40,000 sq. ft., or 0.025 × lot area (capped at 2,600 sq. ft.) on larger lots; in both tiers a 200 sq. ft. bonus applies when the home has no attached garage. Setbacks differ by district: R-1 requires 40 ft front / 40 ft corner-side / 20 ft interior-side; R-2, R-3, R-4 require 30 ft front / 30 ft corner-side / 10% of lot width or 10 ft interior-side (3 ft on lots ≤20,000 sq. ft.). Rear setback is 3 ft in all districts. Maximum height is 15 ft (lots <40,000 sq. ft.) or 24 ft (lots ≥40,000 sq. ft.). The shed must be anchored to the ground on two opposite sides, and a thickened-slab foundation is required if any shed door is wider than 6 ft.