Lot Coverage Limits: Honolulu vs Waipahu
How do lot coverage limits rules compare between Honolulu, HI and Waipahu, HI?
Honolulu and Waipahu have similar restriction levels.
Honolulu, HI
Honolulu County
Honolulu County's LUO Section 21-3.70-1 caps impervious surface at 75 percent of lot area for residential dwellings permitted after May 1, 2019, to control runoff and preserve neighborhood character.
View full Honolulu 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 | Honolulu | Waipahu |
|---|---|---|
| Impervious cap | 75 percent | 75 percent |
| Effective date | May 1, 2019 | May 1, 2019 |
| Code section | ROH 21-3.70-1 | ROH 21-3.70-1 |
| Applies to | New residential dwellings | - |
| Stream overlay | - | Chapter 14 drainage |
Highlighted rows indicate differences between cities.
Honolulu FAQ
How much of my lot can I cover with buildings and pavement in Honolulu?
For residential dwellings permitted after May 1, 2019, ROH 21-3.70-1 caps impervious coverage at 75 percent of lot area. Older homes are subject to the standards in effect when permitted.
Do driveways count toward lot coverage?
Generally yes. Driveways, walkways, patios, and similar hard surfaces count toward the 75 percent impervious cap under ROH 21-3.70-1. Pervious pavers with approved drainage may be credited.
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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