Do I need a permit for a backyard retaining wall?
By My Yard Editorial Team · 7/28/2026
The Quick Answer
Almost universally, walls over 4 feet tall (measured from the bottom of the footing) require a permit and an engineered design. Under 4 feet is usually exempt — but tiered walls can legally count as one tall wall.
The Witty Breakdown
The footing measurement trips everyone up. A wall that looks 3 feet tall with a 12-inch buried base is a 4-foot wall on paper.
Building without the permit means an unpermitted structure on your property record, which becomes a fun surprise at closing.
Step-by-Step Fix
- 1
Call your building department and ask for the exposed-height threshold in writing.
- 2
Ask specifically how tiered walls are measured in your jurisdiction.
- 3
Get a stamped engineered design for anything over the threshold or holding a driveway.
- 4
Schedule inspections at excavation and backfill stages.
Pro-Tip / Do Not Do This
Don't build a tall wall in two 'short' tiers to dodge the permit. Inspectors have seen it, and the geotechnical math doesn't care.
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