The SSOAP toolbox is a suite of computer software tools used for the quantification of Rainfall-derived infiltration and inflow (RDII) and helps with capacity analysis and condition assessment of sanitary sewer systems. This toolbox includes EPA’s stormwater Management Model Version 5 (SWMM5) for performing dynamic routing of flows through the sanitary sewer systems. The RDII prediction methodology offers an effective means to design a focused sewer condition assessment program and maximize the success of field investigation efforts. Also, it provides an effective means to assess the post-rehabilitation performance of the sewer system using the pre- and post-sewer capacity analysis. This tool is complex and not recommended for use by non-technical users.