Avondale, AZ Fence Regulations: Retaining Walls (2026)

Avondale's Zoning Ordinance Section 28-297 addresses walls and fences but does not establish a distinct freestanding retaining-wall height limit; instead, structural walls are reviewed under the City's adopted Building Code, which Avondale references directly in Section 28-297(c)(5) for walls over seven feet. Arizona cities generally apply the International Residential Code, under which a retaining wall is exempt from a permit only when it is not over four feet in height measured from the bottom of the footing to the top of the wall and does not support a surcharge. Retaining walls taller than four feet, or any wall with a surcharge from adjacent structures or unbalanced loading, must be designed by an Arizona registered design professional (engineer) and submitted with the permit application. Where a retaining wall also serves as a screen or yard wall, the combined structure must still meet the zoning height limits in Section 28-297(c) and the material standards in Section 28-297(b). Because grade, drainage, and surcharge conditions vary by lot, homeowners should confirm the exact permit and engineering requirements with Avondale Development Services before building any retaining wall.