What is NMSA?

The National Municipal Stormwater Alliance or NMSA is a 501(c)(3) devoted to supporting Municipal Separate Storm Sewer System (MS4) permittees. We are the only national stormwater organization comprised of, operating on behalf of, and for the benefit of, MS4 permittees.

NMSA is an alliance of state and regional groups made up of MS4 permittees and focused specifically on MS4 issues. Our vision is to help communities tackle stormwater challenges to provide clean water for the nation.
From polluted water
From polluted water


Stormwater runoff is the only major source of water pollution that is increasing in many parts of the United States. Urban runoff is an issue affecting our nation’s economy, communities, and environment.  In order to meet the rising challenge of stormwater pollution, source control must be improved and the function of stormwater infrastructure must be enhanced.

To clean water


NMSA’s vision is to support MS4 permittees across the country, enabling them to develop efficient and effective stormwater programs. NMSA will serve as a voice for MS4 communities, advocating for science-based policies and better understanding of local stormwater management programs.  NMSA will represent the specific concerns of the MS4 sector at the national level with one unified voice.

Working Together, We Will:

A storm drain in a neighborhood
  • Represent MS4 permittees at the national level by providing a unified voice
  • Lead changes in regulation both proactively and reactively
  • Connect and unite MS4 programs
  • Promote stormwater as a resource
  • Improve public understanding and engagement in stormwater solutions
  • Create opportunities for multi-benefit and multi-use stormwater projects

NMSA Action Areas

Sector Support and Information

  • Pursue projects at a national scope that are of interest to and benefit MS4 permittees.
  • Transfer information and technology between state and regional MS4 groups.
  • Communicate with member MS4s about multiple topics using a variety of platforms to disseminate information.
  • Assist in managing existing or forming new state- and regional-level MS4 organizations.
  • Coordinate with national organizations that impact the MS4 sector, including WEF’s Stormwater Institute and its member associations.

Policy & Advocacy

  • Speak directly with U.S. EPA staff and provide a conduit to federal regulatory and legislative contacts.
  • Provide strategic support on regulatory and legislative actions at the state and local levels.
  • Provide formal comments on federal regulatory proposals from the perspective of MS4 permittees.
  • Provide timely communications on pending and ongoing regulatory and legislative actions impacting the MS4 community.
  • Provide policy analyses to the MS4 community.
  • Coordinate and work with other national groups to amplify messages on MS4 issues.


  • Provide forums for exchanging information, experience, and materials among MS4 permittees.
  • Create or support the development of technical reports and guidance materials.
  • Host technical forums and support member activities and conferences.
  • Support and expand public education for stomwater.

Messaging and Communication

  • Distribute information about court rulings and new rules and regulations.
  • Collect, create, and distribute public education materials related to MS4 programs and policies.
  • Explore national media campaigns and other initiatives to expand and amplify public education for stormwater.

NMSA Leadership

Scott Taylor
NMSA Chair – Scott Taylor of the California Stormwater Quality Association

Scott is a Senior Vice President with Michael Baker, International. He is a nationally-recognized stormwater expert with more than 30 years of experience in stormwater quality, flood control, and stormwater management. Scott is a former board member and remains active with the California Stormwater Quality Association (CASQA). With CASQA, Scott helps lead statewide efforts to develop pragmatic and sustainable policies and stormwater management programs. Contact Scott. 

NMSA Vice Chair – Randy Neprash of the Minnesota Cities Stormwater Coalition

Randy is a Project Manager and Stormwater Regulatory Specialist with Stantec as well as a staff member of the Minnesota Cities Stormwater Coalition. The coalition is an organization of about 130 cities regulated under EPA’s MS4 stormwater permitting program. Randy has advised many public and private agencies on issues related to Total Maximum Daily Load studies and implementation plans, low impact development, and alternative stormwater management. Contact Randy.

Randy Neprash