Maricopa County, AZ Fence Regulations: Retaining Walls (2026)
Key Facts
- Max height
- 8 ft outside building envelope
- Permit trigger
- Retaining walls over 18 inches
- Combined wall+fence cap
- 16 ft total height
- Tiered wall spacing
- 3 ft minimum, centerline to centerline
- Enforcement
- Class 2 misdemeanor, daily separate offense
Summary
In unincorporated Maricopa County, retaining walls outside the main building envelope can't exceed 8 feet, and any retaining wall over 18 inches requires a county building permit before construction.
Outside the principal building envelope, the retaining wall height shall not exceed 8'. Retaining walls shall not exceed a height of 8 feet as measured from the low side finished grade to the top of the earth being retained, except as permitted in Article 901.4 of this Ordinance. ... A building permit is required for walls/fences over 6' in height, retaining walls over 18" in height, pool barriers, walls/fences on hillside lots, corrals in residential zoning districts, fences to establish a primary use or a wall on a corner lot abutting a key lot.
Full Breakdown
The Maricopa County Zoning Ordinance caps retaining wall height at 8 feet outside the principal building envelope, measured from low-side finished grade to the top of retained earth. Walls built in a tiered series must be at least 3 feet apart centerline-to-centerline, and if a fence or wall is erected on top of a retaining wall, the combined height tops out at 16 feet. A county building permit is required for any retaining wall over 18 inches tall, along with walls/fences over 6 feet, pool barriers, and walls on hillside lots. Homeowners in unincorporated subdivisions need Planning & Development sign-off before pouring footings.
Violations & Fines
Building without a permit or exceeding the 8-foot/16-foot combined height limit is a zoning violation and public nuisance: a class 2 misdemeanor, with civil penalties up to the misdemeanor's maximum fine per day the violation continues.
Frequently Asked Questions
Do I need a permit for a retaining wall in unincorporated Maricopa County?
How tall can a retaining wall be on my property?
Sources & Official References
Other rules in Maricopa County
Compare Maricopa County to another location·View the Arizona fence regulations overview
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