Guides / Fences and walls · Updated
How tall can a retaining wall be without a permit?
From the International Residential Code as quoted by local building departments, checked November 2026. Your town has the final say.
Short answer
Under the IRC, up to 4 ft measured from the bottom of the footing, as long as nothing heavy sits above it. Count the buried course and gravel base: a 3 ft wall can be 4 ft from the footing. Some towns, including in California, draw the line at 3 ft showing, and any wall with a driveway, slope or building above needs a permit at almost any height.
The rules we found
| Where | Rule |
|---|---|
| IRC R404.4 (model code) | Design required for walls holding back more than 48 in of unbalanced fill, or over 24 in that also carry a load (a surcharge) |
| IRC R105.2, as Port Townsend, WA quotes it | No permit for walls "not over 4 feet in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge" |
| Sandy Springs, GA | No permit at 4 ft or less from the bottom of the footing without a surcharge; engineered design at 6 ft or taller |
| Snohomish County, WA | Permit and engineered plans over 4 ft total height, including the buried part |
| Placerville, CA | No permit up to 3 ft of exposed wall without a surcharge (California Building Code) |
| Grand Prairie, TX | Plans stamped by a Texas engineer for walls that need design under R404.4 |
Measure from the footing
Block makers bury the first course, about 1 in per foot of wall height and 6 in at least, and set it on 6 in of compacted gravel (Allan Block). A wall that shows 3 ft is about 4 ft from the bottom of the gravel. That's why theretaining wall calculator shows both heights.
What counts as a surcharge
Anything that adds load behind the wall: a driveway or parking pad, a slope rising above the wall, a shed, a pool, or the footing of another wall too close behind it. Port Townsend: "Retaining walls that will support a surcharge require an engineered design, and a building permit, regardless of height."
Too tall? Terrace it
Two shorter walls can replace one tall one, if the gap between them is at least twice the lower wall's height. Seeterraced retaining wall spacing or plan it with theterrace planner. Call 811 before you dig, and ask your building department: this page isn't legal advice.