The New Hampshire Department of Environmental Services (DES) received funds in 2002 from the New Hampshire Estuaries Project (NHEP) to provide assistance to coastal communities to develop storm sewer infrastructure maps. This final report describes the grant projects that were completed in Portsmouth and Seabrook. NHEP chose to fund stormwater infrastructure mapping projects for a number of reasons. Primarily, this grant was established in order to fulfill one of the water quality action plans identified in the NHEP Management Plan. In addition, the Coastal/Piscataqua watershed has been identified by DES as a priority watershed in need of restoration. A good map is an important part of identifying pollution sources in the storm drainage system.