Many of Washington, DC’s streams and rivers have become severely eroded and polluted, due largely to unmanaged runoff from a city that is 43% impervious. Through its successful in-stream restoration efforts, DC has improved water quality and reconnected communities to nature. However, stormwater retrofits are particularly challenging in a city so heavily developed – and the price tag for restoring DC’s waterways dwarfs available public funds. This tremendous challenge prompted the District’s adoption of new stormwater management regulations in 2013, requiring green infrastructure to be installed by development and redevelopment projects. A first-of-its-kind Stormwater Retention Credit (SRC) Trading Program offers compliance flexibility to help make the new regulations possible. The SRC Program creates a financial incentive in which voluntary green infrastructure projects can generate credits to be sold to regulated projects. In 2017, the District launched its $11.5 million SRC Price Lock Program to accelerate the pace of green infrastructure retrofits where they are needed most to protect and restore District streams and rivers. The SRC Price Lock Program enables voluntary retrofit projects to lock in a price to sell credits to the city if they are not sold to a regulated site. This creates a price floor in the SRC market, which offers revenue certainty to project developers and helps the city get more out of its limited funding and regulatory tools. Interviews with DC’s Department of Energy and Environment and local stakeholders reveal the growing interest from private investors and SRC aggregators and show the benefit of green infrastructure for healthy waterbodies and communities.