Why Stormwater ?

Stormwater runoff is the only major source of water pollution that is increasing in many parts of the United States. Smart solutions, policies, and investments are needed to tackle this growing problem.

Solving Stormwater

Solving stormwater problems will require the work of many organizations, governments, sectors, and people. Solving stormwater issues requires an alliance.

Join the Alliance

Together we are working to solve problems caused by urban runoff in order to provide the nation with clean water.


The National Municipal Stormwater Alliance or NMSA is a 501(c)(3) with state and regional members made up of Municipal Separate Storm Sewer System (MS4) permittees. NMSA is devoted to supporting MS4 communities, helping them tackle stormwater challenges so that together we can achive our vision of providing clean water for the nation.


Welcome to NMSA’s newly redesigned website. NMSA is a growing organization launched in 2016. We are working to expand our online resources to best support our members and the nation’s MS4 communities. Please take a look around and contact us with your thoughts and comments.

Upcoming Events

Featured Resource

NMSA Tweets

  • International LID Conference in Nashville 2018. Call for abstracts open until 1/16/18. See: https://t.co/f8KHzjvkQM2 months ago
  • Join is for a free webinar on the use of trees in stormwater programs: Trees and Stormwater: A Tool for Your Commun… https://t.co/5iIC1vdkZh3 months ago


Join the Alliance

Learn how you can become an NMSA member today.

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