At what flow rate should mains ideally be flushed?

Flushing mains at a flow rate of 5 feet per second is ideal because this speed is generally considered effective for removing sediment and debris that may accumulate in the pipes over time. This rate ensures that water is moving quickly enough to create turbulence within the pipe, which helps to dislodge any buildup on the walls and carry it away. Flushing at this rate also helps maintain the quality of the water by preventing stagnation and minimizing potential corrosion or biofilm growth within the system.

Moreover, flowing at 5 feet per second strikes a balance between effective flushing and not causing undue stress on the pipe infrastructure. If the flow rate is too high, it could potentially lead to pipe erosion or damage due to increased velocities. On the other hand, lower flow rates might not generate sufficient force to effectively clean the system. Therefore, 5 feet per second is often recommended to ensure efficient maintenance of water quality and pipe integrity.