Cities Stepping Up to Help Reduce 10 Trillion Gallons Worth of Polluted Water Dumped into U.S. Waterways Each Year

New Report: 14 Cities Prove that Green Infrastructure Cleans Waterways, Cuts Costs and Greens Cities

WASHINGTON, D.C. (November 16, 2011) – Cities of all sizes are tackling their water pollution problems, such as stormwater runoff and sewage overflow, by employing green infrastructure and design – and they will save money as a result, according to a peer-reviewed report released today by the Natural Resources Defense Council. The report provides detailed case studies analyzing how 14 cities are using these methods and encourages the EPA to advance these solutions nationwide later this year.                                         

“Every single day, millions of gallons of good water needlessly drain away, filling our waterways with sewage and urban pollutants, rather than replenishing our water supply,” said NRDC Water Program Director David Beckman. “But it doesn’t have to be that way. By making our communities literally greener, we can make our water sources cleaner too – and with much greater return than conventional solutions.”

Rooftops to Rivers II details common water pollution problems and provides case studies for 14 geographically diverse cities that can all be considered leaders for employing green infrastructure solutions to address their pollution problems. The cities featured in the report have improved their ability to manage stormwater and reduce runoff pollution, saved money and beautified their cityscapes by capturing rain where it falls.

“Cities of all sizes are recognizing that green infrastructure – which stops rain where it falls – is the smartest way to reduce water pollution from storms,” said Karen Hobbs, NRDC senior policy analyst. “It often only takes a fraction of an inch to trigger this kind of pollution. And the extreme weather we’ve seen in much of the country this year – from drought to floods and hurricanes – drives home the need for smarter solutions to our water woes.”

The 14 cities featured in the report are all positioned on a six-point “Emerald City Scale” to assess how each of these trailblazing leaders is doing. They are listed here from the highest to lowest points scored:

  • Philadelphia, PA (6)                            
  • Milwaukee, WI (5)
  • New York, NY (5)
  • Portland, OR (5)
  • Syracuse, NY (5)
  • Washington, D.C. (5)
  • Aurora, IL (4)
  • Toronto, Ontario, Canada (4)
  • Chicago, IL (3)
  • Kansas City, MO (3)
  • Nashville, TN (3)
  • Seattle, WA (3)
  • Pittsburgh, PA (1)
  • Detroit Metro Area & the Rouge River Watershed, MI (1)

The six-point scale identifies the primary actions every city can undertake to maximize their green infrastructure investment, including: a long term green infrastructure plan for the city, a retention standard, a requirement to reduce existing impervious surfaces using green infrastructure, incentives for private-party action, guidance or other assistance in deploying green infrastructure, and a dedicated funding source.

Only one city, Philadelphia, is undertaking all six actions, but each city featured in the report is undertaking at least one.

Green infrastructure – in contrast to paved and other impermeable surfaces – stops runoff pollution from the start, by capturing rainwater and either storing it for future consumer use or letting it filter back into the ground, replenishing vegetation and groundwater supplies. Examples include green roofs, street trees, increased green space, rain barrels, rain gardens, and permeable pavement. These design solutions have the added benefits of beautifying neighborhoods, cooling and cleansing the air, reducing asthma and heat-related illnesses, lowering heating and cooling energy costs, boosting economies, and supporting American jobs.

The report details how green infrastructure is frequently more cost-effective than traditional approaches to addressing runoff, like pipes and holding tanks. The City of Philadelphia estimates that a traditional approach to its sewage overflow problems would have cost billions more than its state-approved green infrastructure plan, which will achieve comparable results as it transforms 34 percent of the city’s impervious surfaces to “greened acres.” The American Society of Landscape Architects recently surveyed its members and found that green infrastructure reduced or did not influence costs 75 percent of the time.  EPA’s own analysis shows that green infrastructure approaches save money for developers, communities and, the vast majority of the time, for new development. 

As the EPA prepares to update its national standards for controlling runoff pollution from new development and existing paved areas this winter, these cities’ successes should encourage the agency to adopt requirements that will drive similar approaches nationwide. By requiring sources of polluted runoff to retain water on site, communities will not only better control pollution from contaminated stormwater and sewage, but also reap the numerous benefits that green infrastructure provides.

To complement Rooftops to Rivers II, NRDC also unveiled a new web platform focused on stormwater pollution and modern runoff management approaches. The website,, contains useful information to aid stormwater management decision-makers, and features an interactive tool to survey cities about green infrastructure strategies being used to control stormwater. This will allow municipalities to submit their own green infrastructure programs and see how their cities’ activities fit on the Emerald City green infrastructure scale.

The new report follows up on NRDC’s initial Rooftops to Rivers, published in 2006, revisiting eight cities profiled in the initial report to measure the success of those cities’ green infrastructure programs.

The complete NRDC report is available at