Water distribution pipe maintenance is a global concern. In this study, we propose a Rehabilitation In-Pipe Robot (R-IPR) to perform pipe rehabilitation operations and contain induced contamination. The robot features three modules: a pipe cleaning module, a mechanical sealing module, and an in-pipe manipulator module. This study emphasizes the comprehensive design of the mechanical sealing module. We introduce a multi-layer compound structure of the seal to deal with two characteristics of tuberculated pipe surfaces: 1. macroscopical surface roughness, 2. overhang in foundation profile. The prototype excels in sealing foundation overhang and requires 45% lower compression load than a baseline seal to function. The prototype seal is integrated into the R-IPR. Finally, experiments of the overall system demonstrate the successful performance of the first contamination-less in-pipe rehabilitation.