Unidirectional Flushing Program

Slow moving water in the water mains allows mineral and sediments to deposit and accumulate over time. These deposits can result in water color and water quality problems and contribute to the corrosion of some of the pipes. Unidirectional Flushing (UDF) is a method of cleaning the water mainlines through a network of flushing specific sequences of pipes with the water moving in one direction and being discharged from a fire hydrant.
Flushing will generally occur from 8:00am to 4:30pm for most areas. The hydrants in the certain areas will be open and discharging the water. There may be a slight drop in pressure or a presence of discoloration from the minerals and sediments that are being flushed out. Service should not be disrupted during the flushing process.

For more detailed information about the program try our UDF Information Sheet.


  • Improving water quality in water mains
  • Reduce bacterial growth
  • Restore disinfectant residual
  • Improve colour and turbidity
  • Control corrosion
  • Help restore flow and pressures in system

Details and Specifications

For an up to date progress of the UDF program try our current UDF Map 2018

Flushing for the 2018 UDF program will start on July 26, 2018.