Many of the nation’s watersheds and estuaries are suffering from water quality impairments that limit their ability to support recreation, shellfisheries, and aquatic ecosystem diversity. Under the Clean Water Act (CWA), one of the main mechanisms for addressing impairment is through the establishment of total maximum daily loads (TMDLs), which limit the allowable amount of pollutant loads to a water body. Despite significant progress in Chesapeake Bay and its tributary watersheds over the past two decades, meeting TMDL limits often presents challenging tradeoffs regarding where and how to control sources of pollution. In recognition of past unsuccessful restoration strategies for the Chesapeake Bay, President Obama signed Executive Order (EO) 13508 “Strategy for Protecting and Restoring the Chesapeake Bay Watershed� in 2009. This order requires federal agencies to work together to bring new resources and tools to the Bay restoration effort, including new approaches to implementing the CWA and new funding to promote voluntary efforts by farmers. The first test of the strategy involves implementing plans to achieve the Bay-wide TMDLs, which set maximum nitrogen, phosphorus and sediment target loads for the major tributaries of the Bay. The goals are ambitious and long-term success requires that all new sources be offset in order to maintain target loads in the face of population growth. While there is expansive public support for the Bay restoration goals, the substantial costs create barriers to success.