A gusher is the most severe form of an ingress of water into sewer pipes under constant pressure through a defective or faulty joint. The term is used to describe a deficiency identified during pipe inspection. It is the service condition of a fast-flowing leak into a sanitary sewer system.
Other modifiers are seeper, dripper, and runner.
Trenchlesspedia Explains Gusher
Over time, traditional sewer systems degrade and develop deficiencies. During periods of wet weather or intense storms, defective sewer pipes can take on excess water which can cause sewage overflows and overwhelm treatment plants. Inspectors label water leaks into the system as seepers, drippers, runners or gushers depending on the amount of water and speed of the ingress.
This problem is referred to in terms of infiltration and inflow, commonly called “I & I.” Inspections can be done with CCTV. The issue is a major concern for local municipalities and water utilities. Along with problems at the treatment plant, excess water can cause sewage backups and ecosystem disruption, and can increase associated costs.