Permit briefing
Do you need a permit for a retaining wall?
A retaining wall needs no permit under the International Residential Code up to 4 ft, measured from the footing's bottom, unless it holds up a surcharge.
The reliable short answer
Measure it the way the code does, from the bottom of the footing, and name everything that will bear on the soil behind it before asking whether it is exempt.
Planning complexity
High
Local answer required
Yes
The model code’s answer
How tall can a retaining wall be without a permit?
4 feet under the International Residential Code, measured from the bottom of the footing to the top of the wall, and only while it supports no surcharge: no driveway, building or other load on the soil it holds back. The buried footing counts, so a wall showing 3 feet above ground on a footing more than a foot deep is already past the line. A separate section decides when it must be engineered: past 48 inches of unbalanced fill with nothing bracing its top, or past 24 inches when it resists loads besides soil.
| Rule | What it exempts |
|---|---|
| Model code (IRC R105.2) | Up to 4 ft from the bottom of the footing, no surcharge |
| Austin | Up to 4 ft, no surcharge, not in a flood hazard area |
| Los Angeles | Up to 4 ft, no surcharge or sloping earth, never on a slope over 1 in 5 |
Both checked cities keep the model's 4 feet and add to it. Austin rules out flood hazard areas, and its environmental code draws a second line at 4 feet: outside urban watersheds, cut and fill may go no deeper, with listed exceptions. Los Angeles adds sloping earth to the surcharge test and excludes steep sites outright, and the soil a wall moves there can need a grading permit of its own.
A three-step permit decision
1. Count the footing
The model code, Austin, Houston and Los Angeles all measure from the bottom of the footing to the top of the wall. A wall with 3 feet showing and a footing more than a foot down is already past the 4-foot line. San Diego and Phoenix measure from the top of the footing instead, and set lower lines: 3 feet and 40 inches.
2. Name the load behind it
A driveway, parking or a building on the retained soil is a surcharge, which ends the exemption at any height; Los Angeles adds sloping earth. Separately, the model code wants an engineered design past 48 inches of unbalanced fill, or past 24 inches when the wall resists loads besides soil.
3. Ask about the dirt, not only the wall
Austin's environmental code caps cut and fill at 4 feet of depth outside urban watersheds, with listed exceptions, and Los Angeles needs a grading permit for most cut and fill beyond a shallow excavation or a thin layer of fill. The soil a wall moves can need its own approval.
What Austin and Los Angeles say about a retaining wall
Austin
- No permit
- A retaining wall no more than 4 feet high, measured from the bottom of the footing to the top of the wall, that supports no surcharge and stands outside flood hazard areas.
- Permit
- Anything taller, loaded or in a flood hazard area needs a permit, and with no residential form named for retaining walls, Development Services (512-978-4000) says which one to file. Outside urban watersheds the city's environmental rules also cap cut and fill at 4 feet of depth, with listed exceptions.
Los Angeles
- No permit
- A wall up to 4 feet from the bottom of its footing to its top, supporting no surcharge or sloping earth and impounding no flammable liquids: the building code does not apply to it. That never holds on a slope steeper than 1 in 5.
- Permit
- Taller, loaded, holding back a slope or on steep ground, it needs a building permit. The soil moved to build it can need a grading permit of its own: only a shallow cut, under 2 feet deep or leaving no cut slope over 5 feet steeper than 1 in 2, or a fill under 1 foot on ground flatter than 1 in 10 is exempt, and neither past 50 cubic yards or once the work changes how water drains.
- Valuation
- Masonry retaining wall, per square foot of wall$10
- Concrete retaining wall, per square foot of wall$14
What to have ready before you call
- Height from the bottom of the footing to the top of the wall, at the tallest point
- Everything above it: driveway, parking, a building, a rising slope
- Depth of cut or fill and the cubic yards moved
- Where water behind the wall will drain to
- Flood hazard area, watershed or hillside status of the lot
- Distance to the property line and to any easement