National Municipal Separate Storm Sewer System (MS4) Needs Assessment Survey

New MS4 Needs Assessment Survey Results Report Now Available

The WEF Stormwater Institute has completed two iterations of the National Municipal Separate Storm Sewer System (MS4) Needs Assessment Survey – the first in 2018 and the second in 2020. The primary objectives of these surveys are

  • to better understand MS4 program challenges,
  • to identify the information and resource needs of MS4 permittees, and
  • to approximate current funding levels and estimated funding needs in the MS4 sector.

In the 2020 survey, WEF received 804 responses from 47 states, the District of Columbia, and Puerto Rico.

The WEF Stormwater Institute gratefully acknowledges the MS4 Survey Work Team for their contribution to the development and deployment of the survey, as well as the analysis of the results.

2020 National MS4 Needs Assessment Survey Results Report (February 2021)

In addition to the report, several appendices are available below for additional information

A new feature of the MS4 Needs Assessment is the Data Dashboard that enables users to filter data by permittee type, geographic region, and other characteristics. This information can improve understanding of the challenges, needs, and drivers for stormwater programs. The Data Dashboard is powered by 2NDNATURE Software.

June 3, 2021 Webcast Recording – WEF MS4 Survey and Dashboard: Stormwater Data Coming Alive

2018 National MS4 Needs Assessment Survey Results

In 2018, the WEF Stormwater Institute polled more than 600 MS4 permittees in the first attempt of its kind to identify common challenges and needs among the diverse array of U.S. stormwater managers. Results of the survey underscored broad needs for dedicated sources of funding, infrastructure renewal or replacement, and clearer regulations among respondents.

2018 Survey Results – Executive Summary (September 2018)

2018 Survey Results – Full Report (May 2019)

Press Release: First-Ever Stormwater Needs Survey Shows $7.5 Billion Annual Funding Gap (May 2019)

If you would like any additional information or have questions, please email Bianca Pinto at