Manholes can be rehabilitated and pass a vacuum test for a fraction of the cost of replacing it.

Beyond being environmentally hazardous, sanitary sewer overflows are a constant headache for many public works directors. Much time is spent on inspecting and repairing the main lines, but the manholes can easily be forgotten. Manholes can be a major source of infiltration; reports have shown that manholes and other underground structures can account for 30 to 50 percent of a system's infiltration. This infiltration can occur at manhole rings, through loose mortar and precast joints and around mainline or stub-out connections. Fallen bricks and mortar can block the sewer flow, and may eventually lead to collapse, seriously endangering the surface and surrounding environment.