Everything You Need to Know About MS4 Mapping Grants

The MS4 Mapping Grant Program

In December of 2024, 38 projects across New York State were awarded funding, ranging from a maximum of $75,000 for a single entity to a maximum of $400,000 for a consortium, through the Non-Agricultural Nonpoint Source Planning and Municipal Separate Storm Sewer System Mapping Grant (NPG). This reimbursement grant program is offered by the state and was created to encourage municipalities to improve resiliency against the impacts of climate change by focusing on reducing the amount of polluted stormwater runoff entering local bodies of water (such as lakes, rivers, and streams).

The NPG Program supports the initial planning of non-agricultural nonpoint source water quality improvement projects, as well as state permit-required storm sewer mapping in urban areas, also known as MS4 mapping. (Note: “MS4” is the abbreviation for “municipal separate storm sewer system.”)

Why These Grants Exist

MS4 maps are generally created to display the drainage and outfalls of a municipal separate storm sewer system, which includes publicly-owned pipes, ditches, and other conveyances that collect stormwater and transport it to local waterways. MS4 permits require municipalities to create a Stormwater Management Program Plan (SWMPP) in order to implement methods to manage stormwater discharges into and from the separate storm sewers.

The methods developed from MS4 maps and SWMPPs ensure that the necessary steps are being taken to identify areas where stormwater pollution is an issue and needs to be reduced, to reduce pollution in stormwater runoff, and to ensure that municipalities remain in compliance with the Clean Water Act.

Grant Specifications and Awards

The NPG Program is offered through the New York State Consolidated Funding Application (CFA), so applications are accepted once a year during a window that is open from the springtime through the end of July. Walden will post reminders and information about the 2025 CFA, so stay tuned!

To be considered for NPG funding during the 2024 application period, municipalities had to either be regulated by the MS4 general permit or be a soil and water conservation district on behalf of regulated MS4 operators.

The NPG Program aims to encourage cooperation among MS4 operators, but it also allows municipalities to apply as individuals. Awarded funding must be used to complete comprehensive stormwater system maps. The 2024 requirements for the NPG Program included the following:

• Mapping had to be created or expanded in a GIS program
• At a minimum, the following needed to be included in the GIS mapping:
  • Basic mapping elements, including MS4 outfalls and interconnections
  • Storm sewer conveyance systems
  • Storm sewer structures
  • Post-construction stormwater management practices
  • Municipal facilities
  • Focus areas
  • Sewershed boundaries
  • Discharges to a total maximum daily load (TMDL) watershed, for a given pollutant, as identified in the MS4 General Permit
• Simultaneous mapping of intermediate and advanced mapping elements, along with the basic elements, was permitted. Click here to view all mapping elements

In 2024, MS4 operators that applied as a collaborative were eligible to be awarded grants of up to $60,000 per municipality, with a maximum grant award of up to $400,000 per MS4 collaborative. For MS4 operators that applied as an individual, the maximum grant award was $75,000.

How Walden Can Help

In Rounds 3 and 5 of the NPG, Walden successfully applied for funding on behalf of two Hudson Valley municipalities. Through close collaboration with these clients, our staff prepared NPG applications that were competitive enough to be selected for award. In 2022, the first municipality was awarded $22,500. In 2024, award amounts increased significantly; thus, the second municipality was awarded the new maximum grant amount of $75,000.

Walden’s team of experts is ready to assist you in navigating the application process for NPG funding. Contact us today at 516-548-2974 to learn how we can support your efforts to reduce the amount of polluted stormwater runoff entering lakes, rivers, and streams, and to improve resiliency against the impacts of climate change.