Water quality trading (WQT) under the Clean Water Act is an option for compliance with effluent limitations in a NPDES permit. EPA’s 2003 WQT Policy and 2007 WQT Toolkit for Permit Writers provide guidance to states, interstate agencies, and tribes on how to facilitate trading consistent with the CWA and its implementing regulations. EPA’s February 6, 2019 Memorandum provides additional guidance and policy options, including baseline flexibility concepts, to stakeholders for developing and implementing water quality trading.

Water quality trading can provide greater flexibility on the timing and level of technology a facility might install, reduce overall compliance costs, and encourage voluntary participation of non-point sources within the watershed. Trading can provide ancillary environmental benefits such as carbon sinks, flood retention, riparian improvement, and habitat.

View a map of CWA water quality trading in the U.S. in 2016 below: