Will County, IL Building Setbacks & Zoning: Lot Coverage Limits (2026)

Section 155-3.30(B)'s lot and building table fixes the ceiling by district: 20% in E-1, E-2, R-1 and R-2; 25% in R-2A; 30% in R-3; 40% in R-4; and 45% in R-5 and R-6, the county's multi-family district and the highest allowance on the residential table. The same table separately caps accessory building floor area, from 3,000 square feet in E-1 and E-2 down to 1,200 square feet in R-4, R-5 and R-6, and limits accessory building height to 25 feet in every residential district under footnote [6].

Because the table lists only a percentage, the Zoning Administrator applies the measurement rule of § 155-18.10(D): building coverage is measured along the building line and counts only building area beneath a roof, so a roofed porch counts but an uncovered deck, patio or terrace does not. A footnote to the § 155-3.30(B) table also exempts accessory, ground-mounted solar energy systems for personal household use and beehives from the coverage count, so adding rooftop-free solar arrays or hives never forces a homeowner to shrink an existing house or garage to stay compliant.

A property that exceeds its district's coverage percentage is a zoning violation under § 155-17.20(B)(1), enforced by the Zoning Administrator. For non-emergency violations the county must give notice describing the violation and allow ten days to correct it before pursuing further enforcement (§ 155-17.20(H)(1)); each week the violation remains uncorrected after notice is a separate violation (§ 155-17.20(C)). Remedies include withholding or revoking permits, stop-work orders, and court-ordered injunctive relief or abatement (§ 155-17.20(D)). Enforcement decisions may be appealed to the Planning and Zoning Commission under § 155-16.100 (§ 155-17.20(H)(3)).