The City of Mission will be cleaning watermains through a process called unidirectional flushing beginning March 14, 2023 for approximately 6 weeks in the following areas:

From 14th Avenue to 7th Avenue and Nelson Street to Stave Lake Street, as indicated on the map below:

Work will begin at 8:00am and end at 5:00pm, Monday through Friday. Each day, an area of approximately five (5) city blocks will be cleaned.  The process will create extremely discolored and debris-laden water as the water main side walls are scoured to remove any accumulated debris.

Only residences with full water interruption will receive a letter from City staff advising of the scheduled interruption. Notices will be delivered door-to-door and a day in advance of the scheduled cleaning. Please be advised, if you do not receive a letter, you can expect your water service to remain on for the duration of the project.

What is Unidirectional Flushing?

Unidirectional Flushing (UDF) is a method of cleaning the inside of watermains within the distribution system. This UDF technique allows high flow velocities of water by isolating certain sections of watermains. This higher velocity water flow allows for better scouring of the inside wall of the watermains.

The UDF program is completed by closing water valves in a specific manner to create water movement in one direction while opening fire hydrants at the end of that section. Maintaining this flushing sequence is important so that the water used during flushing remains clean.

Why Unidirectional Flushing?

Slow-moving water in the distribution system allows sediment and bacterial growth to accumulate over time. These deposits can result in water quality problems and contribute to the corrosion of some of the water distribution systems. UDF inactivates bacterial growth, increases disinfectant residual, improves colour, removes turbidity and restores flow in the water distribution system.

What are the Benefits of Unidirectional Flushing?

The benefits are improving water quality, colour, and flow of clean water through the distribution system. A preventative maintenance program is also implemented on valves and hydrants in conjunction with the UDF program.

When Will Unidirectional Flushing Take Place?

The UDF program will begin on March 14, 2023 Mondays to Fridays, 8:00 am to 5:00 pm and can take up 6 weeks to complete.

Will Residents Be Affected?

Please be advised that water valves and fire hydrants near your residence may be used to discharge water onto the street for several minutes. There may be a slight drop in water pressure or a presence of discoloration from the minerals and sediments that are being flushed out of the watermains. Your water service should not be disrupted during the flushing process. If discoloration is noticed in your water, please turn the tap off for 15 minutes. Then flush from your bathtub tap or outside tap until the water runs clear.