Retaining Walls: Ewa Gentry vs Urban Honolulu
How do retaining walls rules compare between Ewa Gentry, HI and Urban Honolulu, HI?
Urban Honolulu has fewer restrictions than Ewa Gentry.
Ewa Gentry, HI
Honolulu County
ROH Sec. 21-4.40 controls retaining walls in Ewa Gentry, limiting fill-containing walls inside required yards to six feet and combining terraced wall heights for measurement.
View full Ewa Gentry 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 | Ewa Gentry | 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.
Ewa Gentry FAQ
Can I build two stacked retaining walls to exceed the height limit?
No. ROH 21-4.40 combines terraced wall heights so stacking does not bypass the six-foot limit in required yards.
Do I need an engineer for a rear-yard retaining wall?
Most fill-retaining walls above the short-wall exemption require engineered drawings and a DPP permit.
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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