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SetbackIQ

Do you need a permit for a retaining wall in Phoenix, AZ?

It depends on the details of your project.

The exempt height for retaining walls is 40 in under the 2024 amendments.

A wall that holds back a driveway or slope needs a permit at any height.

The height is measured from the bottom of the footing.

A person last checked these rules on October 19, 2026. This is guidance only, so confirm with Phoenix before you build.

Check your exact lot

Your zoning district sets the setbacks, and a flood zone can change the permit answer. Enter your address to see both.

What are you building?

Permits a retaining wall can need in Phoenix

PermitWhen it applies
Building permitPhoenix's 2024 amendment shows both 4 ft and 40 in as the exempt height. SetbackIQ uses the stricter 40 in.Medium confidence
Floodplain development permitGrading and walls in a FEMA special flood hazard area need a floodplain permit.

Local details

  • Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
  • HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.

How to apply

Common questions

When does a retaining wall need a building permit in Phoenix?
Phoenix's 2024 amendment shows both 4 ft and 40 in as the exempt height. SetbackIQ uses the stricter 40 in. A wall 40 in or less from footing to top, with no load above it, needs no permit in Phoenix.
Where do I apply for a retaining wall permit in Phoenix?
Apply through Phoenix SHAPE PHX permits, or call (602) 262-7811.

Sources

  1. Phoenix Building Construction Code 2024, Sec. 105.1 and 105.2 (other items). Checked 2026-10-22
    Retaining walls that are not over [4 feet / 40 inches; the amended text shows both] in height... unless supporting a surcharge... Interior and exterior platforms, sidewalks and driveways not more than 30 inches (762 mm) above adjacent grade... Prefabricated…
  2. 44 CFR 59.1, definition of development (NFIP). Checked 2026-10-19
    Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures...
  3. 44 CFR 60.3, floodplain management criteria. Checked 2026-10-19
    Require permits for all proposed construction or other development in the community...