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

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!”

Rain Barrel Distribution

Rain barrels are a simple, eco-friendly way to store and use rain water captured by your roof’s gutter system. Rain barrels can save you money by providing free H2O to help water your lawn and garden, or even wash your car. To place an order for a reasonably-priced rain barrel and accessories, visit http://www.upcyclerainbarrel.com 2020 RainContinue reading “Rain Barrel Distribution”

Become a Certified Inspector!

Join professionals from the Oklahoma Water Survey for a one-day training to become a certified inspector on erosion and sediment control practices on construction sites. The program educates attendees on proper installation, maintenance and inspection of erosion and sediment control measures and provides an understanding of stormwater regulations and requirements for Oklahoma.Certification lasts for threeContinue reading “Become a Certified Inspector!”