Stormwater Management: Honolulu vs Mililani Mauka
How do stormwater management rules compare between Honolulu, HI and Mililani Mauka, HI?
Honolulu has fewer restrictions than Mililani Mauka.
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 →Mililani Mauka, HI
Honolulu County
Mililani Mauka properties connected to the city's separate storm sewer system fall under ROH Chapter 43, Article 11, which bars non-stormwater discharges and enforces MS4 water quality rules.
View full Mililani Mauka rules →Key Facts Comparison
| Fact | Honolulu | Mililani Mauka |
|---|---|---|
| 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.
Mililani Mauka FAQ
Can I drain my Mililani Mauka pool into a storm drain?
No. Chlorinated pool water is a prohibited non-stormwater discharge under Sec. 43-11.22 and must be dechlorinated and discharged according to city guidance.
What about washing paint brushes in my driveway?
Paint and solvent residues that reach the storm drain are prohibited discharges; clean brushes in a sink connected to the sanitary sewer instead.
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