Retaining Walls: Mesa vs Phoenix
How do retaining walls rules compare between Mesa, AZ and Phoenix, AZ?
Mesa and Phoenix have similar restriction levels.
Mesa, AZ
Maricopa County
Mesa requires building permits for retaining walls over 4 feet in height including the surcharge. Retaining walls combined with fences on top have cumulative height calculations under the building code.
View full Mesa rules →Phoenix, AZ
Maricopa County
Phoenix requires building permits for retaining walls over 3 feet in height. Combinations of retaining walls and fences always require structural design calculations. Combined wall-fence structures exceeding 9 feet need zoning approval. Walls 3 feet or less are exempt from permits unless on hillside lots.
View full Phoenix rules →Key Facts Comparison
| Fact | Mesa | Phoenix |
|---|---|---|
| Permit Trigger | Over 4 feet high | - |
| Engineering Required | For walls over 4 feet | - |
| Fence Combo | Cumulative height applies | - |
| Code Reference | Title 4, Building Regulations | - |
| Permit Threshold | - | Over 3 ft requires permit |
| No Permit Needed | - | 3 ft or less (non-hillside) |
| Combo Walls | - | Always require structural calcs |
| Zoning Approval | - | Required if combo exceeds 9 ft |
| Hillside Lots | - | All retaining walls need permits |
Highlighted rows indicate differences between cities.
Mesa FAQ
Do I need a permit for a retaining wall in Mesa?
Yes, if the retaining wall exceeds 4 feet in height including surcharge. Engineered plans are required for the permit application.
Can I put a fence on top of a retaining wall in Mesa?
Yes, but the combined height of the retaining wall and fence is regulated. Check with Mesa Development Services for the maximum allowed height in your zoning district.
Phoenix FAQ
Do I need a permit for a retaining wall in Phoenix?
Unsurcharged retaining walls 3 feet or less do not require a permit (unless on a hillside lot). Walls over 3 feet require a building permit with structural design calculations. Combined retaining wall/fence structures always require structural calculations.
How is retaining wall height measured?
Height is measured from the bottom of the footing to the top of the wall, not from the top of the soil. A railing or view fence on top of a retaining wall is permitted up to 40 inches if needed for pedestrian safety.
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