Honolulu vs Kailua
How do rainwater harvesting rules compare between Honolulu, HI and Kailua, HI?
Honolulu and Kailua have similar restriction levels.
Honolulu, HI
Honolulu County
Honolulu County has no ordinance restricting residential rainwater harvesting; the Board of Water Supply encourages it countywide through a rain barrel rebate program and CTAHR catchment guidelines.
View full Honolulu rules →Kailua, HI
Honolulu County
Kailua residents can collect rainwater for outdoor irrigation without a permit; the Board of Water Supply offers rebates for rain barrels on windward lots.
View full Kailua rules →Key Facts Comparison
| Fact | Honolulu | Kailua |
|---|---|---|
| County ordinance | None | - |
| Permit threshold | Up to 360 gallons exempt | 360 gallons storage |
| Rebate program | Board of Water Supply | - |
| Guidelines | UH CTAHR catchment program | - |
| State restrictions | None | - |
| Code reference | - | Hawaii Plumbing Code Ch. 16 |
| Rebates | - | BWS rain barrel program |
| Indoor use | - | Requires plumbing permit |
Highlighted rows indicate differences between cities.
Honolulu FAQ
Do I need a permit for a backyard rain barrel on Oahu?
Usually no. Exterior catchment up to 360 gallons for outdoor irrigation is exempt under the Hawaii Plumbing Code, and Honolulu County has no separate ordinance.
Are there incentives for catching rainwater?
Yes. The Honolulu Board of Water Supply runs a rain barrel rebate program encouraging conservation. Details and eligibility are posted on the BWS website.
Kailua FAQ
Can I install rain barrels on my Kailua home?
Yes. Exterior barrels up to 360 gallons for outdoor irrigation are allowed without a permit. BWS offers rebates to offset purchase costs.
Can I plumb harvested water into my Kailua kitchen?
Only with a plumbing permit and proper backflow protection. Indoor use is treated as a non-potable supply under the Hawaii Plumbing Code.
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