Lot Coverage Limits: Mililani Town vs Urban Honolulu
How do lot coverage limits rules compare between Mililani Town, HI and Urban Honolulu, HI?
Urban Honolulu has fewer restrictions than Mililani Town.
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 →Urban Honolulu, HI
Honolulu County
Urban Honolulu caps impervious surface at 75 percent of lot area for residential dwellings permitted after May 1, 2019, under ROH 21-3.70-1 to manage runoff into the city's storm drains.
View full Urban Honolulu rules →Key Facts Comparison
| Fact | Mililani Town | Urban Honolulu |
|---|---|---|
| - | - | |
| Impervious cap | - | 75 percent |
| Effective date | - | May 1, 2019 |
| Code section | - | ROH 21-3.70-1 |
| Flood concern | - | Ala Wai drainage |
Highlighted rows indicate differences between cities.
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.
Urban Honolulu FAQ
How much of an Urban Honolulu lot can be paved?
For residential dwellings permitted after May 1, 2019, ROH 21-3.70-1 limits impervious coverage to 75 percent. Older homes follow the standards in effect when they were permitted.
Do pool decks count toward Honolulu lot coverage?
Generally yes. Pool decks, patios, driveways, and roofed accessory structures count toward the 75 percent impervious cap under ROH 21-3.70-1. Pervious pavers with approved drainage can earn partial credit.
Compare other topics
See how Mililani Town and Urban Honolulu compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool