Lot Coverage Limits: East Honolulu vs Mililani Town
How do lot coverage limits rules compare between East Honolulu, HI and Mililani Town, HI?
East Honolulu has fewer restrictions than Mililani Town.
East Honolulu, HI
Honolulu County
East Honolulu residential lot coverage follows ROH 21-3.70-1, which caps impervious surface at 75 percent for dwellings permitted after May 1, 2019, impacting Hawaii Kai marina and ridge parcels.
View full East Honolulu rules →Mililani Town, HI
Honolulu County
Mililani Town residential lots follow ROH Sec. 21-3.70-1 impervious caps. Homes permitted after May 1, 2019 are limited to 75 percent impervious coverage, with HOAs often requiring additional landscaped area.
View full Mililani Town rules →Key Facts Comparison
| Fact | East Honolulu | Mililani Town |
|---|---|---|
| Impervious cap | 75 percent | - |
| Effective date | May 1, 2019 | - |
| Code section | ROH 21-3.70-1 | - |
| Drainage overlay | Chapter 14 applies | - |
| - | - |
Highlighted rows indicate differences between cities.
East Honolulu FAQ
What is the Hawaii Kai impervious limit?
Dwellings permitted after May 1, 2019 cap impervious surface at 75 percent of the lot under ROH 21-3.70-1. Pools, driveways, and patios count toward the limit, pushing designs toward permeable surfaces.
Do older Portlock homes have to comply?
Pre-2019 homes that exceed the 75 percent cap are typically legally nonconforming. Substantial redevelopment or expansion can trigger full compliance with the current ROH 21-3.70-1 limit.
Mililani Town FAQ
Can I extend my driveway to fit an extra vehicle?
Possibly, but confirm total impervious coverage stays under 75 percent and HOA approves the revised frontage design.
Does a covered lanai count as impervious?
Yes, roofed lanais typically count as impervious for coverage calculations, even if the floor is open slab or deck.
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