McHenry County, IL Fence Regulations: Retaining Walls (2026)
Key Facts
- UDO height cap
- None specific for walls
- Location rule
- Wall must be within lot lines
- Structural review
- Adopted building code (Title 15)
- Drainage
- Stormwater review may apply
- Authority
- UDO § 16.56.050H.1.b
Summary
The McHenry County UDO sets no separate height cap for retaining walls, but a 'fence or wall' must sit entirely within your lot lines. Structural retaining walls are reviewed under the adopted building code, and grading near water may trigger a stormwater permit.
A fence or wall, including all posts, bases, and other structural parts shall be located completely within the boundaries of the lot on which it is located. The installation of fencing by a private property owner in the public right-of-way is prohibited.
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
The UDO fence provisions (§ 16.56.050H.1.b) expressly apply to a 'fence or wall,' requiring the whole structure and its footings to be within your boundaries and out of the public right-of-way. The UDO does not fix a numeric height limit for retaining walls; instead, structural retaining walls are permitted and inspected under McHenry County's adopted building codes (Title 15), and taller walls typically need engineered plans. Because retaining walls change grade and drainage, work in or near a floodplain, wetland, or regulated area can require review under the county Stormwater Management Ordinance. Cities such as Crystal Lake apply their own engineering standards.
Violations & Fines
A retaining wall built without required building-code review, or one that encroaches over a lot line or alters drainage onto a neighbor, can draw a correction order, after-the-fact permitting, or removal.
Frequently Asked Questions
Does McHenry County limit retaining wall height?
Can a retaining wall sit on the property line?
Sources & Official References
Other rules in McHenry County
Compare McHenry County to another location·View the Illinois fence regulations overview
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