Retaining Walls: Kailua vs Mililani Mauka
How do retaining walls rules compare between Kailua, HI and Mililani Mauka, HI?
Kailua and Mililani Mauka 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 →Mililani Mauka, HI
Honolulu County
ROH Sec. 21-4.40 limits fill-retaining walls in Mililani Mauka yards to six feet and combines terraced wall heights, important on the community's sloped Central Oahu grades.
View full Mililani Mauka rules →Key Facts Comparison
| Fact | Kailua | Mililani Mauka |
|---|---|---|
| - | - |
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.
Mililani Mauka FAQ
Can I build a three-tier terrace instead of one tall wall?
Terraced walls are measured together under ROH 21-4.40, so stacking tiers does not sidestep the six-foot limit.
Must retaining wall finishes be approved by MTA?
Yes. Walls visible from the street typically require MTA approval for color and finish.
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