City and County of Honolulu's Storm Water Management Program
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What is stormwater? Learn more about stormwater, storm drain systems and pollution.
Latest News

In April, join the City to celebrate Earth Month! Scheduled activities and events focus on the mauka to makai connection. Participants will learn about water quality and best management practices that can reduce pollution to our waterways.

New NPDES permit issued
The City and County of Honolulu's storm drain system is regulated under a National Pollutant Discharge Elimination System (NPDES) municipal separate storm sewer (MS4) permit. The most current permit, NPDES Permit No. HI S000002, was issued on January 16, 2015 by the Hawaii Department of Health to the City and County of Honolulu. The effective date is February 16, 2015 until midnight, January 15, 2020.

State of Hawaii House Bill 1325
Introduced State of Hawaii House Bill 1325 will authorize counties to assess user fees for stormwater management.
Click here for more details.
Take the CleanWaterHonolulu Pop Quiz!

Try our new Everyday Clean Water Hero pop quiz to see how much you know about storm water!
Frequently Read Documents
NPDES Permit No. HI S000002 issued on January 16, 2015
Final Storm Water Management Program Plan, June 22, 2012
Rules Relating to Storm Drainage Standards, effective June 1, 2013.
Best Management Practices (BMP) Manual for Construction Sites (PDF 7.4MB)
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