Stormwater is the only growing source of water pollution in many waterways across the United States. With urban populations expected to grow and more frequent and intense storms occurring across the country, there is ever-increasing pressure on stormwater systems and water infrastructure.


With municipal separate storm sewer system (MS4) permittees facing the brunt of these challenges, the Water Environment Federation’s (WEF) Stormwater Institute wanted to learn directly from MS4s about what information and resources are needed. WEF conducted a national survey of MS4 permittees to identify the needs of these permittees and to better understand stormwater program challenges.

In total, the survey received 622 responses from 48 states and the District of Columbia. The survey respondents were generally representative of the size variability and geographic distribution of MS4s across the United States.


Survey respondents indicated their need for additional information and technical resources related to six broad topic areas. Respondents were also asked about needs related to the six minimum control measures (MCM) and other aspects of permit compliance.


Of the six broad stormwater topic areas, both Phase I and II MS4 respondents indicated the greatest need for information and technical resources related to funding and financing by a wide margin. Secondary areas of need include information on green infrastructure (GI) practices and other innovative approaches, as well as asset management.


Nontraditional and state department of transportation responses also indicated the greatest need for information and resources related to asset management, total maximum daily load (TMDL) compliance, and GI and other innovative best management practices. When considering MCM areas of interest, the need for information is spread relatively evenly across all six areas, with slightly greater interest in post-construction runoff control, and somewhat less of a need for information on industrial sites as well as pollution prevention and nonstructural controls.


Phase I and II MS4 respondents were also asked to rank their program challenges. Lack of funding or availability of capital, aging infrastructure, and increasing or expanding regulations were ranked as the most important challenges, and aging workforce, lack of technical expertise, and lack of information and training on best practices were the least important. Nontraditional and state DOT respondents provided very similar ratings for program challenges with the exception of aging infrastructure, which appears to be less of a challenge for state DOTs, and funding capacity and evolving regulations, which are lesser challenges for nontraditional MS4 permittees.


An additional survey section focused on the drivers for MS4 planning and investment decisions. Reponses from Phase I and II permittees were relatively consistent and ranked regulatory compliance, local and pluvial flooding, and water quality and habitat restoration issues as important drivers. Drivers of lowest significance for MS4s were associated with water supply issues, climate change, large-scale and riverine flooding, and wet-weather dynamics associated with urban runoff (such as combined sewer overflows and sanitary sewer overflows). State DOT MS4 permit holders also see regulatory compliance as well as water quality and habitat restoration as significant drivers, but place flood control as a lower priority.


An unexpected finding in the survey results is the lack of priority regarding climate change, revealing the need to highlight changing precipitation patterns effects on MS4s. These education opportunities could focus on extreme events and investigate the impacts of recent episodic flood events.


Budget & Funding Needs


Funding and financing are the areas of greatest challenge and highest need, in terms of both information and resources. The survey section that addressed this topic in greater depth was based upon two questions that asked about the respondent’s estimated annual stormwater program budget, and if the estimated budget was adequate to meet current stormwater goals (including regulatory compliance). If respondents indicated that their annual stormwater budget was not adequate, a follow up question clarified the estimated additional amount required to meet goals and be fully compliant.


Forty-eight percent of respondents indicated that they did not have the resources needed to meet stormwater program goals. Phase I MS4 communities and state DOTs have the largest budgets and indicated less need for additional budget (by percentage) compared to Phase II MS4s and nontraditional permittees. Of the Phase I and II MS4 permittees that indicated a need for additional funding, the total need increases with size of population served. For example, the average additional annual need for permittees serving 50,000 people or less is approximately $1.2 million compared to $9.6 million for communities serving 500,000 people or more.


Based on the data collected in the survey, the annual funding gap in the MS4 sector is an estimated $7.5 billion.


First Steps into the Future


An important step in a maturing infrastructure sector is to better understand the fundamental challenges and needs. This survey represent this first major step in the stormwater sector, which is a field that is notoriously data-poor. By collecting data, this effort identifies the priorities that need to be addressed in the near-term, while allowing for planning for coverage of other areas in a long-term strategic fashion.


The results of the inaugural National MS4 Needs Assessment Survey led by the Stormwater Institute reflects an effort to learn more about the nature and needs of the MS4 sector at a scale that has never been attempted. In addition, this survey has brought to light some surprising and significant findings that will help to inform the Stormwater Institute as it moves ahead in efforts to meet the needs of the MS4 sector.


The report can be downloaded here.


See Discussion, Leave A Comment