Retaining Walls: Kapolei vs Urban Honolulu
How do retaining walls rules compare between Kapolei, HI and Urban Honolulu, HI?
Urban Honolulu has fewer restrictions than Kapolei.
Kapolei, HI
Honolulu County
ROH Sec. 21-4.40 limits fill-containing retaining walls in Kapolei to six feet within required yards and combines terraced wall heights for compliance measurement.
View full Kapolei rules →Urban Honolulu, HI
Honolulu County
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.
View full Urban Honolulu rules →Key Facts Comparison
| Fact | Kapolei | Urban Honolulu |
|---|---|---|
| - | - | |
| Max height | - | 6 feet |
| Terracing rule | - | Combined height |
| Permit trigger | - | Over 30 inches |
| Code section | - | ROH 21-4.40 |
Highlighted rows indicate differences between cities.
Kapolei FAQ
Can I stack two three-foot walls to build a six-foot terrace?
Terraced walls are measured together, so stacking does not avoid the six-foot cap in required yards under 21-4.40.
Do I need a permit for a short planter wall?
Planter or retaining walls under 30 inches are often exempt, but check ROH 18-3.1 and HOA rules before starting.
Urban Honolulu FAQ
How tall can a retaining wall be in Urban Honolulu?
Under ROH 21-4.40, retaining walls containing fill within required yards cannot exceed 6 feet. Terraced walls on hillside lots in neighborhoods like Manoa are measured as one combined wall.
Does a hillside retaining wall need a permit in Honolulu?
Yes, if it exceeds 30 inches. ROH 18-3.1 exempts only walls 30 inches or shorter. Honolulu DPP typically requires engineered plans, drainage, and guardrails for larger hillside retaining walls.
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