EPA’s Response to the Current Status of CSO Control Efforts Development of New Tools and Guidance

EPA’s combined sewer overflow (CSO) program has reached a mature stage. Some communities
have completed their CSO controls, while others are in the process of constructing controls or
evaluating potential alternatives. With the recent emphasis on green infrastructure, some
communities are evaluating the role of natural systems and ecological processes in Long Term
Control Plans (LTCPs) for controlling CSOs. The convergence of these critical milestones and
issues for the national CSO program highlights the need for updated tools and guidance to
facilitate future CSO control efforts. In response, EPA is developing guidance on post
construction compliance monitoring for CSOs, as well as the Green LTCP-EZ, a tool that allows
small CSO communities to incorporate green infrastructure as part of their LTCP efforts. This
paper discusses these initiatives serves as outreach to CSO communities on these efforts.