Water industry representives from across North America check out the Paseo Verde green roof in North Phila. Credit: Brian Rademaekers/Philadelphia Water.
Water industry representatives from across North America check out the Paseo Verde green roof in North Phila. Credit: Brian Rademaekers/Philadelphia Water.

Green City, Clean Waters is the biggest plan in the U.S. designed to manage stormwater with green infrastructure, and that means Philadelphia Water will take all the help it can get from developers who want to add value to their properties while also lessening the negative environmental impacts with green stormwater tools.

On October 8th, Councilwoman Blondell Reynolds Brown, Chair of the Council Committee on the Environment, introduced a bill that would give the development community a new incentive to include one of the most talked about green infrastructure tools out there – green roofs.

Brown’s bill would allow for density zoning bonuses for developers who incorporate approved green roofs into building designs.

“As a City, we have been steadily increasing incentives to build green roofs, and it is working. Philadelphia is now the number three City in North America when it comes to green roof square footage, trailing only Washington, D.C. and Toronto, Canada; that is huge,” Councilwoman Reynolds Brown said in statement released by her office.

Green roofs would have to meet Philadelphia Water's design standards to qualify for the density bonus, and Commissioner Howard Neukrug offered support for the new bill.

“We thank Councilwoman Reynolds Brown for helping to provide this added incentive that will create more green roofs in Philadelphia,” said Neukrug. “Green roofs help to manage stormwater, keeping it from overwhelming our sewer system and polluting our rivers. This legislation will also help make green roofs more affordable and help create more jobs for our local green business community.”

Under the current code, a 10,000 square foot lot in a Residential Multi Family Zoning District (RM-1) would be zoned for twenty dwelling units. If the developer added an approved green roof to the design, the same lot would be zoned for 27 units.

In a Neighborhood Commercial Mixed Zoning District (CMX-2 and CMX-2.5) a 10,000 square foot building is currently zoned for 19 dwelling units and under the new law, would be zoned for 27 units, provided they install an approved green roof.

A green roof is defined by the ordinance as “a treatment to a rooftop that supports living vegetation and includes a synthetic, high quality waterproof membrane, drainage layer, root barrier, soil layer, and vegetation layer.”

Philadelphia would join a small but growing number of cities offering density bonuses for green roofs including San Diego, Portland, Ore., Chicago, and Austin. The bill will be referred to the Committee on the Rules, Chaired by Councilman Bill Greenlee, who expects a fall 2015 hearing.

To see a full copy of the bill, please click here.