Watermain Cleaning and Flushing

We conduct unidirectional water main flushing - or hydrant flushing - from May to October. This is part of our ongoing commitment to provide safe drinking water in the City of St. John's. Flushing ensures we provide the highest quality drinking water in our water distribution network.

Flushing activities generally occur on weekdays from 8 a.m. to 4 p.m. for most areas.

It takes about 30 to 60 minutes to flush water through each hydrant.

Open external page https://www.youtube.com/embed/hG89Tz0pELE?wmode=transparent

Unidirectional flushing involves discharging water from fire hydrants. We open and close valves in a specific sequence to create water movement in one direction. This type of flushing increases the speed of the water flow in the watermain. This produces a scouring action and removes sediment deposits. Flushing starts at a clean water source, like the water treatment plant. It moves towards the outer limits of the City. This ensures that clean water is always used to flush the mains.

In conventional flushing, the water used does not always begin at the clean water source. The speed of the water is much slower than during unidirectional flushing. This means more water is required to thoroughly clean the watermains.

Most large cities have some type of flushing program to clean their watermains. Water professionals say this the best way to improve water quality. Unidirectional flushing increases the reliability of the water distribution system. The amount of water lost in the process is a small price to pay to keep the quality of your water high.

Stay informed

When we are planning to visit an area for watermain (hydrant) flushing, we will post advisories on the website and send an email to our subscribers.

During flushing

When we arrive in your neighbourhood for flushing, we will place digital signs in the area. We urge everyone to use caution while traveling around operations and entering areas of water accumulation.

When you see flushing operations on your street, avoid using water for any purposes that need clean water. Avoid preparing food and beverages, doing medical and dental procedures, or laundry. You should also avoid using your hot water system. This will reduce the amount of sediment drawn into your hot water tank.

There may be a slight drop in pressure or discolouration. This is from the minerals and sediments that are being flushed out of the system. Flushing should not disrupt your service.

After flushing

After the flushing, the water can be cloudy, milky or have a chlorine smell for several hours. These issues are temporary and typically clear within a few hours.

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.
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.

Tips for clearing your water

Turn on a cold water tap and let the water run for a few minutes, we recommend using the cold-water faucet on a bathtub.
Do not choose a tap that has a water filter connected to it, or the sediment may clog your filter.
Do not use a hot water tap because it could draw sediment into your hot water tank.
Catch some water in a light-coloured or white cup or container to see if it is clear. You can use your water if it is clear.
If the water does not clear in 15 minutes, wait 30 minutes and try again.
If the water is still discoloured after three or four hours, contact the Access Centre.