Retaining Walls: Kailua vs Pearl City
How do retaining walls rules compare between Kailua, HI and Pearl City, HI?
Kailua and Pearl City have similar restriction levels.
Kailua, HI
Honolulu County
Retaining walls in Kailua follow ROH Sec. 21-4.40, which caps fill-retention walls within required yards at 6 feet. Terraced walls count toward combined height totals, and most walls over 30 inches require engineering.
View full Kailua rules →Pearl City, HI
Honolulu County
Pearl City retaining walls on the Pearl City Highlands and Manana hillsides fall under ROH 21-4.40, capping fill-bearing walls in required yards at 6 feet and combining terraced heights.
View full Pearl City rules →Key Facts Comparison
| Fact | Kailua | Pearl City |
|---|---|---|
| - | - | |
| Yard max height | - | 6 feet |
| Terraced rule | - | Heights combined |
| Code section | - | ROH 21-4.40 |
| Drainage review | - | Chapter 14 |
Highlighted rows indicate differences between cities.
Kailua FAQ
Can I build a 5-foot retaining wall in my side yard?
Yes, up to 6 feet within required yards under ROH 21-4.40, but you will likely need a permit and engineering over 30 inches.
What about two stacked 4-foot walls?
Terraced walls are typically measured together, so two closely spaced 4-foot walls may be treated as an 8-foot wall exceeding the cap.
Pearl City FAQ
How tall can a Pearl City retaining wall be?
Walls with fill in a required yard cap at 6 feet under ROH 21-4.40. Terraced walls are measured as combined height, and engineering review is required above the 30-inch permit threshold on hillside lots.
Do hillside walls need extra review?
Yes. Pearl City Highlands and Manana hillside sites typically require geotechnical and drainage review, engineered drawings, and Chapter 14 grading coordination alongside the 21-4.40 retaining wall rules.
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