Retaining Walls: East Honolulu vs Kailua
How do retaining walls rules compare between East Honolulu, HI and Kailua, HI?
East Honolulu and Kailua have similar restriction levels.
East Honolulu, HI
Honolulu County
East Honolulu retaining walls on Kuliouou, Hawaii Loa Ridge, and Niu Valley hillsides fall under ROH 21-4.40, which caps fill-bearing walls in required yards at 6 feet with terraced heights combined.
View full East Honolulu rules →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 →Key Facts Comparison
| Fact | East Honolulu | Kailua |
|---|---|---|
| Yard max height | 6 feet | - |
| Terraced rule | Heights combined | - |
| Code section | ROH 21-4.40 | - |
| Engineering trigger | Above 30 inches | - |
| - | - |
Highlighted rows indicate differences between cities.
East Honolulu FAQ
How tall can a Hawaii Kai retaining wall be?
Walls containing fill in a required yard cap at 6 feet under ROH 21-4.40. Terraced walls are measured as combined height. Engineering review is required above the 30-inch permit threshold for hillside lots.
Do Kuliouou hillside walls need extra review?
Yes. Steep Kuliouou and Hawaii Loa Ridge sites typically require geotechnical and drainage review, engineered drawings, and sometimes grading permits under Chapter 14 alongside the 21-4.40 retaining wall rules.
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.
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