What is a typical cause of a sewer backup?

The typical cause of a sewer backup, particularly in the context of municipal systems, often involves being overwhelmed by excessive inflow. When there's an influx of water, such as from heavy rainfall or snowmelt, it can exceed the capacity of the municipal sewer infrastructure. This can lead to backups in homes and businesses connected to the system because the excess water has nowhere to go.

While other factors like improper maintenance of household plumbing, tree roots invading sewer lines, and heavy rainfall can contribute to sewer backups, they do not encompass the broader issue of municipal systems being overwhelmed. Municipal systems are designed to manage a certain volume of wastewater. If the volume exceeds this capacity due to rainfall, it can cause significant backflow and flooding problems. Thus, the overwhelming of these systems is a common and significant cause of sewer backups.