By Alisa Valderrama and Larry Levine, Natural Resources Defense Council
Stormwater runoff is a principal cause of urban waterway pollution nationwide, fouling rivers, lakes, beaches, and drinking water supplies. To reduce the environmental and public health threats posed by polluted stormwater and to comply with the Clean Water Act, cities nationwide are making significant investments to reduce stormwater runoff. However, traditional solutions that rely solely on fixing or expanding existing sewer and stormwater infrastructure can be extremely expensive and fail to address the root cause of the problem: impervious spaces in the built environment that generate 10 trillion gallons of untreated runoff per year.
Philadelphia encourages property owners to install green infrastructure techniques with a flagship stormwater billing structure that includes a significant credit (up to nearly 100 percent) for non-residential owners if they manage to keep the first inch of rainfall on their property rather than letting it runoff into the drain.