Urban Honolulu limits retaining walls that contain fill within required yards to 6 feet under ROH 21-4.40 and combines terraced wall heights to prevent stacking around hillside lots.
Many Urban Honolulu neighborhoods such as Manoa, Makiki Heights, Palolo, and St. Louis Heights sit on hillside terrain where retaining walls are essential. ROH/LUO 21-4.40 limits retaining walls containing fill within required yards to 6 feet in height and treats terraced walls as one combined wall for measurement, so stacking two 4-foot walls does not avoid the 6-foot cap. Walls over 30 inches need a permit per ROH 18-3.1, engineered plans, and guardrails where they drop off onto walkways. Drainage, weep holes, and tieback systems are required to prevent saturation failures that are common during Kona storms. Walls near city storm drains must avoid blocking public easements.
Overheight or unpermitted retaining walls on Urban Honolulu hillside lots face stop-work orders, engineered redesign requirements, daily civil penalties, and, where drainage fails, emergency abatement and potential liability to downhill neighbors.
Urban Honolulu, HI
Urban Honolulu enforces the islandwide Land Use Ordinance at ROH 21-4.60 to limit fence, wall, and hedge heights in Waikiki, Ala Moana, Manoa, and other CDP ...
Urban Honolulu, HI
Urban Honolulu property owners obtain fence and wall permits from the Honolulu Department of Planning and Permitting under ROH 18-3.1, which exempts retainin...
Urban Honolulu, HI
Urban Honolulu enforces ROH 21-4.30 setbacks across dense CDP neighborhoods, with residential districts typically requiring 10-foot front yards and 5-foot si...
Side-by-side rule comparisons with other cities in Honolulu County.
See how other cities in Honolulu County handle retaining walls.
See how Urban Honolulu's retaining walls rules stack up against other locations.
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