What it means
Utilities flush dead ends, low-flow areas, and targeted mains to remove accumulated sediment and refresh water. Unidirectional flushing uses planned valve and hydrant operation to create high velocity in a specific direction.
What operators watch
- Flushing can temporarily discolor water or reduce pressure.
- Velocity matters for scouring sediment.
- Public notification and records help reduce confusion and repeat complaints.
Common exam traps
- Assuming flushing is only for aesthetics.
- Ignoring pressure and traffic safety during hydrant operation.
- Confusing routine flushing with main disinfection.
Field example
A dead-end main with recurring low residual may be placed on a scheduled flushing route.
