Central Oklahoma Stormwater Alliance

COSWA  is an organization of MS4s in the Oklahoma City metropolitan area which allows participating MS4s to pool resources to satisfy permit obligations on a regional level.

What We Do

We participate in events and outreach to help teach the local community about water quality and local stormwater issues.

We promote the use of rain barrels to help mitigate pollutant discharges and potential downstream flooding.

We run PSAs on local news and radio stations to increase public awareness of stormwater and other environmental issues.

Regulated MS4s in Oklahoma


Phase I MS4s


Phase II MS4s




Non-Traditional MS4s

Latest News and Updates

Industrial Stormwater Webinar

The City of Oklahoma City Storm Water Quality Management Division will host a WEBINAR geared toward Industrial Storm Water permittees. The webinar will begin at 10:00am on Thursday, February 27th, 2020.  This webinar is FREE and is expected to last approximately 30-40 minutes, with Q&A. The topic for this webinar will include: Industrial Storm Water TrainingContinue reading “Industrial Stormwater Webinar”

Rain Barrel Winner!

Thanks for joining us last month for the OKC Home & Garden Show; it was a busy weekend but we had a great time talking with everyone! Congratulations to Mustang resident Todd Lannert for winning the rain barrel raffle!

Don't Miss a Chance to Win!

Don’t forget to come see us at the Home and Garden Show this weekend! We’ll be at Booth #2048 at the south end of the Centennial Building. Come test your stormwater knowledge to enter a raffle to win a free rain barrel! Home and Garden Show hours: Friday: 12:00 PM – 9:00 PMSaturday: 10:00 AMContinue reading “Don't Miss a Chance to Win!”