New York Citys efforts to improve water quality are a critical part of PlaNYC, Mayor Bloombergs blueprint for a greener, greater city. Already the Harbor is cleaner than it has been in over 100 years, and millions of people enjoy the Citys waterfront and waterways every year, thanks in part to the New York City Department of Environmental Protections (DEPs) investment of billions of dollars in sewer and wastewater treatment plant upgrades. But in those waterbodies that do not yet meet water quality standards for pathogens, the biggest remaining challenge is to further reduce combined sewer overflows (CSOs) that discharge a mixture of untreated sewage and stormwater runoff when it rains. Traditional approaches to reduce CSOs further would include the construction of additional, large infrastructure, but the remaining opportunities for such construction are very expensive, and do not provide the sustainability benefits that New Yorkers rightly expect from multi-billion dollar investments of public funds. This Green Infrastructure Plan presents an alternative approach to improving water quality that integrates green infrastructure such as swales and green roofs, with investments to optimize the existing system and to build targeted, smaller-scale grey or traditional infrastructure. This is a multi-pronged, modular, and adaptive approach to a complicated problem that will provide widespread, immediate benefits at a lower cost. The green infrastructure component of this strategy builds upon and reinforces the strong public and government support that will be necessary to make additional water quality investments.