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Water Main Flushing Program

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1. What is water main flushing?

Water main flushing is the process used to clean water mains. Water system valves are turned off to isolate a section of the water main. Water is then flushed through in one direction at high speed to produce a scouring action that removes built-up sediment. Clean water is always used to flush water mains. After flushing, the water exits through an attachment to a fire hydrant.

2. What are water mains?

Water mains are underground pipes that carry water from the reservoir to your street.

3. Why are you "flushing" the water mains?

We clean water mains to improve water quality by removing sediment. Water travels slowly through the mains, causing sediment to settle at the bottom and build up over time. A change in direction or an increase in the rate of flow of the water in the mains (e.g., due to water main breaks, or hydrant use for firefighting) can disturb the sediment and discolour the water.

4. How do you clean the water mains during flushing?

We flush most of the water mains by forcing water through them at high velocity and discharging it through hydrants. This water flow scours and cleans sediment from inside the mains. We leave the hydrant open until the water runs clear. The flushed water will be de-chlorinated before entering the catch basin.

5. How long does it take to flush the water mains on each street?

Flushing takes approximately 30 minutes to an hour. We require all taps to be turned off and no toilets flushed during the flushing time as indicated in the notice to residents for individual households to ensure that the work is done properly.

6. How will I know when you are flushing water mains on my street?

We will notify you via letters delivered to each residence prior to commencement of work. The letter will contain instructions and information on the program. If you live in a multi-family complex, staff will contact your property manager/landlord on when the work will begin and will include information on how long it will take.

7. Can I use my water when you are flushing the water mains on my street?

Do not use your water or flush your toilet when we are cleaning the water mains on your street. Using your water or flushing your toilet could draw sediment into the water pipes of your building, into water filters, washing machines, hot water tanks, etc. Turn off any time-delayed water systems, such as dishwashers, coffee makers, and lawn sprinklers.

8. My in-home medical equipment requires water to operate. What should I do?

Consider rescheduling the use of this equipment before or after the water main flushing. Make sure the cold water tap runs clear before connecting to the in-home water-dependent medical equipment.

9. What do I do if I need water during the time that I am not supposed to use water?

As a precautionary measure you may store a sufficient reserve of potable water for use during the flushing hours.

10. I have time delayed appliances or water conditioning systems. What should I do?

Please turn off all time delayed water line appliances during the flushing period. If you have water conditioning systems such as water softener or filtration system, you may want to shut off the water supply valve to these systems, until after the water main flushing is completed.

11. Is the Fire Department aware of the water main flushing?

Yes. The City of White Rock Fire Department is informed of the flushing time, date, and location. Water for fire suppression is available from the water system at all times during the flushing program.

12. Will I notice anything different after you have flushed the water mains?

Your water may be discoloured. Water is sometimes discoloured after water main cleaning, but this should not last long. Do not use discoloured water for any purpose that require clean water, such as preparing food and beverages, medical and dental procedures, or laundry.

• After flushing is complete, remove the aerator (a fine mesh grid) on your tap. Then, turn on a cold water tap, preferably the laundry tap, and let the water run for a few minutes.
  • Do not choose a tap that has a water filter connected to it; otherwise, the sediment may clog your filter.
  • Do not use a hot water tap because it could draw sediment into your hot water tank. Once the water runs clear place back the aerator.
• Catch some water in a light coloured cup or container to see if it is clear. You can use your water if it is clear.
• If the water does not clear within 5 to 10 minutes, wait two hours and try again.

13. How do I get rid of the discoloured appearance?

Customers are advised to fully open their cold water faucets in their laundry tap, kitchen and/or bathroom to flush this water out of their service piping and plumbing lines. In most cases, the water should begin to run clear again within a minute. If it does not clear, please let us know by calling 604-541-2181 or email the Water Department.

14. What should I do if the water is still discoloured after two or three hours?

If this happens, call 604-541-2181 or email the Water Department.

15. What if someone drinks the water when it is discoloured?

Drinking discoloured water should not make you sick; however, it may not smell, taste, or look pleasant.

16. What else may I notice about my water after you have flushed the water mains?

Immediately after the 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.

17. Why can't you flush the water mains at night?

It is safer for staff to work on the streets in daylight. Also, it is easier in the daylight to see when all the sediment has been flushed out and the water is running clear.

18. Where will you drain the water used in the flushing program?

We will discharge the water into the street catch basins. We will be using an environmentally friendly product (sodium thiosulphate) to remove the chlorine from the water before it is discharged.

19. Does discharged water affect the environment?

No. The City takes special precautions to ensure that the quantity and quality of the water flushed is safe for disposal. Before doing any field work, the City investigates water disposal routes and ensures that they are of adequate capacity to receive the water and are not sensitive to the flow. In most cases, the water is sent to stormwater collection system, or to a drainage ditch. During flushing, the field crew monitors disposal of the water, reduces its energy to prevent erosion, and adds dechlorination pucks to remove any chlorine.

20. Do other cities have similar water main flushing programs?

Many cities have some type of flushing program to clean their water mains. This is considered the best way to improve water quality and increase the reliability of the distribution system.

21. I lost water service. Why, and what do I do?

Though not intentional, this happens from time to time during the flushing program. During flushing, certain valves are closed to provide control over the direction of flow. It is likely that a valve closure resulted in loss of supply to your block. Contact the Engineering and Municipal Operations Department at 604-541-2181 or email the Water Department. The field crew will be sent to your block immediately to investigate and identify which valves may have been inadvertently left closed and will be reopened.

22. Why does flush-water (hydrant or at the tap) appear discoloured?

The colour is due to the presence of solids that are scoured from the surface of the pipes. These may include sand, sediment, iron (rust), and manganese, all of which are naturally occurring and common to virtually every water system. At the levels that cause mild discolouration, these solids are not harmful, although they may impart an undesirable taste to the water.

23. Is the water safe to drink?

Yes, the City has maintained compliance with all provincial and federal drinking water quality standards. The City performs frequent monitoring throughout the system to ensure the safety and aesthetic quality of your water.

24. How will you pay for the water main flushing program?

Funds from the water utility rates will pay for this program. Water rates will not be increased to pay for this maintenance program.

25. Will I be paying for the water used in flushing?

No, each residence and business is individually metered at the service connection to determine consumption. Your utility bill is based on your specific meter readings.

26. Is water main flushing a waste of water? Is this counterproductive to conservation?

No. We are using a unidirectional flushing technique, which uses less water than conventional flushing. The City strongly values, encourages and practices water conservation measures. In developing the flushing program, the City has considered the impact of water use and weighed it against the known benefits of flushing. While a fair amount of water is used and is necessary to create an effective scour, the City uses a flushing practice called (unidirectional) water main flushing that is specifically designed to reduce overall water usage.