DuPage County, IL Fence Regulations: Retaining Walls (2026)
Key Facts
- Engineering trigger height
- 24 inches (2 feet)
- Who certifies
- Illinois architect or structural engineer
- Plan must show
- Top and bottom wall elevations
- Pre-engineered systems
- Manufacturer spec sheets required
- Governing chapter
- Chapter 8, Building Code
Summary
DuPage County requires grading plans to show retaining wall elevations, and any wall 24 inches or taller needs a licensed Illinois architect or structural engineer's certification.
Top and bottom elevations of the proposed retaining wall, along with a cross-section detail for the proposed design. Walls twenty-four inches (24") or more in height require the certification of a registered Illinois Architect or Structural Engineer. Manufacturer's specification sheets are required for walls that are pre-engineered (e.g. pre-cast inter-locking wall system, etc.). Depending on type of wall system, height, etc. the above certification may also be required, along with as-built drawings of the installation.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).
Full Breakdown
Under the county Building Code's grading plan requirements, anyone submitting a grading plan for unincorporated DuPage County must show the top and bottom elevations of any proposed retaining wall plus a cross-section detail of its design. Once a wall reaches 24 inches in height, the plan needs certification from a registered Illinois architect or structural engineer, and pre-engineered systems like precast interlocking block walls need the manufacturer's spec sheets on file too. The Building Official can also require as-built drawings after installation.
Violations & Fines
A grading plan missing required retaining wall elevations, cross-sections, or (for walls 24 inches and up) engineer certification will be rejected by the Building Official before a permit issues; uncertified walls built without the required plan approval are subject to the county's building code enforcement process.
Frequently Asked Questions
Does my retaining wall need an engineer's stamp in DuPage County?
Can I use a precast interlocking block system without an engineer?
Sources & Official References
Other rules in DuPage County
Compare DuPage County to another location·View the Illinois fence regulations overview
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