Lot Coverage Limits: Mililani Mauka vs Waipahu
How do lot coverage limits rules compare between Mililani Mauka, HI and Waipahu, HI?
Waipahu has fewer restrictions than Mililani Mauka.
Mililani Mauka, HI
Honolulu County
ROH Sec. 21-3.70-1 imposes impervious-surface caps on Mililani Mauka lots, including a 75 percent impervious limit for dwellings permitted after May 1, 2019.
View full Mililani Mauka rules →Waipahu, HI
Honolulu County
Waipahu lot coverage follows ROH 21-3.70-1, capping impervious surface at 75 percent for dwellings permitted after May 1, 2019, straining tight plantation and multi-generational lots.
View full Waipahu rules →Key Facts Comparison
| Fact | Mililani Mauka | Waipahu |
|---|---|---|
| - | - | |
| Impervious cap | - | 75 percent |
| Effective date | - | May 1, 2019 |
| Code section | - | ROH 21-3.70-1 |
| Stream overlay | - | Chapter 14 drainage |
Highlighted rows indicate differences between cities.
Mililani Mauka FAQ
Can I pave over my front yard for more parking?
Full front-yard paving often exceeds the 75 percent impervious cap and conflicts with MTA front-yard landscape rules.
Do decks count toward impervious coverage?
Solid-surface decks generally count as impervious, while open-slatted decks over pervious ground may count less.
Waipahu FAQ
What is the Waipahu impervious limit?
Dwellings permitted after May 1, 2019 cap impervious surface at 75 percent of the lot under ROH 21-3.70-1. Driveways, patios, and pool decks all count toward the limit on narrow plantation lots.
Do older Waipahu homes need to comply?
Pre-2019 homes exceeding the 75 percent cap are typically legally nonconforming. Substantial redevelopment, demolition, or expansion triggers full compliance with the current ROH 21-3.70-1 impervious cap.
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