Auburn, WA Fence Regulations: Retaining Walls (2026)

025 governs retaining walls citywide, requiring design and construction to meet the adopted International Building Code and International Residential Code standards, and barring any wall from reducing sight distance under the city's engineering design standards. 74 ACC, and subsurface elements like footings, anchors and cantilevers cannot encroach into the right-of-way or public utility easements without the city engineer's permission or explicit easement language. 025(B) creates a three-tier system measured from the bottom of the footing to the top of the wall: walls under 48 inches, built to IRC standards, are allowed in every required setback area regardless of surcharge; walls over 48 and under 84 inches are allowed in setback areas except the front and street-side setback; and walls over 84 inches are not allowed in any setback area at all.

Retaining walls visible from the right-of-way or an adjacent property must be built of rock, textured or patterned concrete, masonry, or composite materials, explicitly ruling out plain smooth concrete or 'ecology blocks,' though the planning director can approve other materials. 50 ACC. A building permit may still be required for a wall regardless of height if trees or other landscape features could impact it, such as through root intrusion, or if it will bear a surcharge load. Retaining walls that are part of an approved preliminary plat, built before the final plat records, are exempt from the setback-area requirements in this section.