Notice To Water Customers
Occasional Discolouration

June 24, 2002

Water customers may occasionally receive water which is discoloured. The water is usually rusty in nature although it can sometimes contain sand or have a muddy appearance.

These events can be the result of watermain breaks and/or a consequence of valves being closed in order to isolate a section of watermain in order to carry out repairs or other servicing. When valves are closed in the water distribution system, the normal pattern of water flow and velocity is disrupted and this can create turbulence in the watermains sufficient to disturb rust or other particles that have accumulated on the inside of the metal pipes.

Customers can experience discoloured water both in close proximity to the watermain break or many blocks, even a kilometre or more away, depending on various factors such as their supply main size, location and demand flows. Unfortunately, it is impossible to predict the location and extent of the customers that may receive discoloured water.

Discolourization of the normal water supply can also occur during the flushing of watermains and this procedure is carried out for several reasons. Firstly, minimum chlorine residual levels must be maintained for disinfection purposes and some dead-end watermains need to be flushed in order to achieve these standards. Secondly, flushing of watermains is required on a regular basis in order to remove rust and other materials that can accumulate in the pipes. Some of this flushing is carried out on a scheduled basis and the customers affected are normally left a notice as to the schedule of work. In some instances, the flushing is carried out on an emergency basis, without advance notice, when chlorine residual testing indicates minimal levels are not present.

When customers encounter discoloured water, they should run their cold-water tap for a period of 20 -30 minutes until such time that normal clear water is being received for at least 5 minutes. A cold-water tap should be chosen which does not have a screen attached to the end of the faucet. Laundry or bathing should not be initiated until such time that the water remains clear for at least an hour or more.

If you experience discoloured water, please contact our Public Works & Services Division Dispatcher at (705)474-4340.