Stormwater Management: Honolulu vs Waipahu
How do stormwater management rules compare between Honolulu, HI and Waipahu, HI?
Honolulu has fewer restrictions than Waipahu.
Honolulu, HI
Honolulu County
Honolulu's storm drain system discharges directly to the ocean, so ROH chapter 14 article 12 prohibits non-stormwater discharges and requires best management practices on construction and industrial sites.
View full Honolulu rules →Waipahu, HI
Honolulu County
Waipahu's dense neighborhoods discharge stormwater toward Pearl Harbor and must comply with ROH Chapter 43, Article 11, which prohibits non-stormwater discharges to the city's MS4 system.
View full Waipahu rules →Key Facts Comparison
| Fact | Honolulu | Waipahu |
|---|---|---|
| Local code | ROH Chapter 14 Article 12 | - |
| Disturbance trigger | 1 acre or more | - |
| State permit | NPDES construction | - |
| City agency | DFM and ENV | - |
| Outfall destination | Direct to ocean | - |
| - | - |
Highlighted rows indicate differences between cities.
Honolulu FAQ
Can I wash my car in the driveway on Oahu?
Occasional residential car washing is generally tolerated, but Honolulu encourages using a commercial wash. Soapy water flowing into the storm drain technically violates the discharge ordinance.
Who do I call to report illegal dumping into a storm drain?
Call the city's Storm Water Quality Hotline operated by the Department of Facility Maintenance. Photos and license plate numbers help inspectors investigate quickly.
Waipahu FAQ
What is an illicit stormwater discharge in Waipahu?
Any non-stormwater flow into the city storm drain, such as soapy water, chemicals, paint, or wastewater, is classified as an illicit discharge prohibited under Sec. 43-11.22.
What if my business rinses equipment outside?
Outdoor rinsing that drains to a storm inlet violates Sec. 43-11.22. Rinse water must be captured, directed to sanitary sewer with permission, or contained to prevent storm drain entry.
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