McHenry County, IL Building Safety: Building Permits (2026)
Key Facts
- Code adopted
- 2021 International Building Code, local amendments
- Permitting department
- McHenry County Planning and Development
- Shed exemption
- 150 sq ft, outside floodplain/wetland
- Exempt fence
- under 8 ft, less than 50% solid
- Exempt retaining wall
- 4 ft or less, no surcharge
- Permit validity
- 2 years, work must start in 180 days
- Minimum fine
- $100 to $500 per offense
Summary
Unincorporated McHenry County enforces the 2021 International Building Code with local amendments under County Code § 15.04.010. Nearly every construction project needs a permit from the Department of Planning and Development, with only narrow exemptions for small sheds, low open fences, short retaining walls, and similar minor work.
SECTION 105 PERMITS a. Revise Section 105.2 "Work exempt from permit. Building: Exemption 1." to read as follows: 1. One-story detached accessory structures used for tool and storage sheds, playhouses, and similar uses, that have a maximum floor area of one-hundred fifty (150) square feet and are not located in a floodplain or wetland and comply with all requirements of the McHenry County Unified Development Ordinance and McHenry County Stormwater Ordinance and are properly anchored... b. ... 2. Open fences that obscure less than fifty percent (50%) of the view through the fence and that have a maximum height of eight (8) feet and are not located in a floodplain or wetland... c. ... 4. Retaining walls that are not over 4 feet (1219 mm) in height measured from the adjacent grade to the top of the wall, unless supporting a surcharge.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2025 S-5: Supplement contains: Local legislation current through Ord. A25-0037, passed 8-19-2025 | State legislation current through ALS 2025 Pamphlet No. 1).
Full Breakdown
2's exempt-work list for McHenry County. Exempt from a building permit: one-story detached accessory structures such as tool sheds or playhouses up to 150 square feet, properly anchored and outside a floodplain or wetland; open fences that obscure less than 50% of the view and stand no more than 8 feet tall; retaining walls no more than 4 feet high unless supporting a surcharge; sidewalks, patios, and driveways no more than 30 inches above grade; agricultural exempt structures holding an Agricultural Exempt Structure Construction Card; and signs the county's Unified Development Ordinance designates as permit-exempt. 1). 5). 1). 2).
Violations & Fines
Section 15.04.020 sets minimum fines per violation category: $200 for new single- or multi-family construction, $500 for new commercial buildings, $200 for a new residential accessory structure, $500 for a signal or transmission tower, $200 for residential alterations, $100 for minor construction, and $200 for a building- or ground-mounted sign. Any violation of the 2021 International Building Code with local amendments carries a $500 minimum fine per offense, and each week a violation stays uncorrected is a separate offense; the county can also seek an injunction instead of or alongside a fine.
Frequently Asked Questions
Do I need a permit to build a shed in unincorporated McHenry County?
How long does a McHenry County building permit stay valid?
What happens if I build without a permit in unincorporated McHenry County?
Is a permit required for a retaining wall on my property?
Sources & Official References
Other rules in McHenry County
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