Inflow/infiltration or clean water entering the collection system can strain capacity and cause overflows.
Identifying sources and mitigating those sources through rehabilitation can significantly improve the performance of the collection system. Water seeping into the system through dead laterals, interstitial flow, and leaking connections is often not just seeping as shown in these videos.
Interstitial flow is ground water that collects between a pipe liner and the host pipe and enters the system at the connection.
Dead laterals that have not been properly capped when they were disconnected can also collect rain and groundwater and transfer it into the collection system.
Separated joints are another common source of I/I. This video shows flows entering the system from the first joint north of a manhole. PACP coding for this defect would be JS (joint separation) and IG (Infiltration Gusher).
This is a plugged pipe with a steady stream of infiltration. The plugged portion is located further back in the pipe and mud has been carried in by the infiltration coming from the plug. The PACP coding that is assigned for this defect is TFB (Tap Factory Abandoned) and IR (Infiltration Runner).