This technical report describes the new Condition Assessment Support Tool and provides a case study that demonstrates how the rainfall-derived infiltration and inflow (RDII) methodology in the SSOAP Toolbox has been effectively used in sewer condition assessment and rehabilitation to support wastewater infrastructure improvements. The Condition Assessment Support Tool has two primary functions: 1. Prioritizes Sub-Sewersheds for field Investigations to Support Condition Assessment The tool obtains RDII parameters stored in a central database for selected sub-sewersheds and enables graphical and tabular comparisons. This information can be used to prioritize sub-sewershed field investigations and subsequent sewer rehabilitation plans. To accomplish this, a range of RDII parameter is developed, including levels of inflow, infiltration, RDII flow rate/acre, and RDII volume/linear feet of sewer in the sub-sewersheds. 2. Performs a Pre- and Post-Sewer Rehabilitation RDII Correlation Analysis The tool enables graphical and tabular comparison of RDII estimates from two sub-sewersheds (control and rehabilitation) obtained from two different flow monitoring periods (pre-rehabilitation and post-rehabilitation periods). The control sub-sewershed is a sewered area that has not undergone any rehabilitation; is ideally nearby; and, is similar in age, size, land-use, and pipe materials to a sub-sewershed being studied with post-rehabilitation conditions. The control area is used to compare how RDII in pre- and post-rehabilitation periods respond to environmental variations, as a result of system rehabilitation and other improvements. Results can be used to assess the effectiveness of sewer rehabilitation programs.