Percy Street

December 16, 2012 Philadelphia

Case Study Source: The Joint U.S.-Brazil Initiative on Urban Sustainability, part of the U.S. Environmental Protection Agency.


The 800 block of South Percy Street in South Philadelphia showcases the city's first porous green street. The street required excavation for a new sewer, which provided the opportunity to replace the street surface with porous asphalt. Philadelphia streets needing similar reconstruction in the future will be considered for porous application. Porous materials, such as porous asphalt, are specially designed to allow water to soak through a normally impenetrable surface, significantly reducing stormwater runoff from a site. Porous asphalt is as strong as conventional asphalt, but has voids in it that allow water to trickle through the material. By allowing stormwater to infiltrate into the ground instead of flowing into the city's combined sewer system, the porous surface on Percy Street helps reduce the negative impacts of pollution and flooding on local streams and rivers.


This project is intended to reduce stormwater runoff and associated combined sewer overflows. It may also extend the life of the street area and reduce snow removal and de-icing needs. This project was funded by the Philadelphia Water Department.

Contact Information

Philadelphia Water Department
Fax: +1 (215) 685-6043
Mail: Office of Watersheds
Philadelphia Water Department
1101 Market Street, 4th Floor
Philadelphia, PA 19107