Pervious pavement is a porous concrete that allows storm water to seep back into the ground. It’s a valuable green tool and can be used for a parking lot, driveway, sidewalk or similar structure—which recharges groundwater and reduces sewer overflow and storm water runoff. It also has been shown to reduce pollution from sediment, phosphorous, nitrogen, zinc, lead and chemical oxygen demand. Soil underneath pervious pavement is aerated more easily, giving nearby trees and plants fuller and more nutritious soil. It can reduce surface temperatures responsible for heat island effect and lower cooling costs. It also helps improve land usage because pervious pavement can eliminate the need for creating retention ponds or other storm water management devices, and can even reduce the cost of a project by eliminating those extra measures to remain in compliance with Environmental Protection Agency storm water regulations.

It is not to be confused with permeable pavement which differs from porous or pervious pavement in that water on the surface of this type of concrete does not pass through the pavement, but rather around the pavers. Similar to other green technologies, pervious pavement was discovered more than three decades ago, but has just recently become a material regularly included in site design.

Porous pavement was developed in 1972 by Philadelphia’s Franklin Institute. To create the pervious concrete, controlled amounts of water and bonding materials are mixed together, forming a thick paste. Unlike other concrete products, pervious pavement contains very little to no sand, which adds density to a material; instead the paste creates a highly permeable material that allows water to filter through it quickly. The highly porous material can reduce the strength of the material compared with other pavement, but for most applications, the material is strong enough. Pervious pavement has many other benefits, including requiring less irrigation for area grass and landscaping due to rainwater seepage; reducing glare and automobile hydroplaning; cutting down on emissions from parked cars in parking structures; and reduce thermal pollution.

Pervious pavement systems can earn development credits in the Leadership for Energy and Environmental Design program from the U.S. Green Building Council. The credits would come in the sustainable sites, materials and resources areas. Cold climates may not be very accommodating of developments with pervious pavement because when water is not sufficiently absorbed through the soil, it may cause a puddle effect that can freeze and deteriorate the pavement. At the same time, when climate is controlled, pervious pavements have been known to reduce skidding on ice.