Watermain Flushing

Flushing the watermains improves water quality by removing sediment that slowly build up at the bottom of the watermain over time.

During uni-directional flushing, water system valves are operated to create one-way flow to isolate a section of water main to be cleaned. A hydrant connected to the main is then opened to remove the built-up sediment. This type of flushing increases the speed of the water flow in the main to about two metres or six feet per second (it is normally less than .3 metres or 1 foot per second). This high speed produces a scouring action in the mains, removing sediment deposits. The flushing starts at a clean water source (e.g., the water pumping stations) and moves through the watermain system. This ensures that clean water is always used to flush the mains.

Staff will update this webpage every few days with which areas will be flushing next.

Our main planned program usually only occurs in late winter/early spring.  We intermittently flush all year round in selected areas where it is needed to maintain water quality.

The City will inform residents before starting the flushing program by posting notices on our website, social media, and other areas. The City also distributes letters and door hangers.

Flushing may cause short-term pressure fluctuations along with discolouration and sediment in the water reaching your home or business.

The water may smell, taste and look different for your usual supply, however the water remains disinfected during the process.

Immediately after cleaning, you may notice that your water is cloudy or has a chlorine smell.

Cloudy water

Water is cloudy when air gets in it and makes tiny bubbles. These bubbles are harmless and will disappear if you let the water sit for a few minutes.

Chlorine smell

We add enough chlorine to the water to keep it safe. You can easily get rid of the chlorine taste and smell by filling a container with water and keeping it in the fridge for drinking – much of the chlorine will leave the water overnight.

The Greater Vancouver Regional District monitors the water quality by sampling and testing at water sampling stations throughout the City on a weekly basis to ensure that the water in the water distribution system is safe to drink.

In addition to removing more sediment and using less water than conventional flushing, watermain flushing tests and exercises the water system valves and hydrants.

Many cities have some type of flushing program to clean their watermains (e.g., conventional flushing or unidirectional flushing). This is considered the best way to improve water quality and increase the reliability of the water distribution system.