Discoloured tap water

Occasionally, the water coming from the taps in your home may appear discoloured.

Here are some frequently asked questions about discoloured water:

What causes discoloured water?

Discoloured water is usually caused by minerals naturally found in groundwater or from the corrosion of older iron pipes in the distribution system. These minerals, over time, build up in the watermains and can be disturbed during maintenance activities such as watermain cleaning, fire hydrant maintenance, or watermain breaks. The City is actively replacing iron watermains during infrastructure renewal projects.

How can I get rid of discoloured water in my home?

When a discolouration event occurs (watermain break, construction, hydrant flushing), it is important to flush the lines in a systematic manner to ensure the discolouration does not spread throughout the plumbing system more than necessary.

  1. Choose a tap as close as possible to where the water service enters the house,
  2. Run the cold water for 10-15 minutes until it clears.
  3. If it doesn’t clear in that time, turn the tap off for 30 minutes and then try again.
  4. Once clear, continue flushing all cold water taps, systematically moving upwards through the residence until all taps run clear.
  5. If you have had discoloured water fill any toilet tanks, the water within the bowl may appear discoloured until the tank clears.

If the issue persists after you have attempted the above, contact 519-837-5627

Occasionally, discoloured water indicates a private plumbing issue:

If only one tap has discoloured water try these steps:

  1. Remove the aerator (screen) from the tap where you are experiencing the discolouration
  2. Run the cold water for 10-15 minutes until it clears
  3. Place the aerator back on your tap
  4. If the issue persists, you may wish to contact a plumber

If only the hot water is discoloured:

the City only provides cold water to customers, so this indicates a private plumbing issue and you may wish to contact a plumber.

Is discoloured water safe?

Drinking small quantities of discoloured water is not likely to cause a health problem. It may not smell, taste, or look pleasant, but tests have shown that it is safe.

In compliance with Provincial regulations, the City maintains a disinfectant residual in all water supplied to ensure customer safety. We work closely with the Wellington-Dufferin-Guelph Public Health on all matters pertaining to the safety of municipal drinking water.

Please contact Wellington-Dufferin-Guelph Public Health for more information on the health effects of discoloured water.

Will it affect my laundry?

It may stain your laundry, particularly whites, so we recommend waiting until the water clears before doing laundry.

About water main cleaning

The City performs routine maintenance throughout the year to make sure our water infrastructure is in proper working order, and you have a safe, reliable water supply.

Water mains are underground pipes that carry water from the pumping stations to your street and the service pipes connected to your house. The City swabs and flushes water mains to remove sediment all year round.

We use high-speed water from hydrants to flush water mains and remove any loose sediment. No chemicals are used during water main cleaning.

We also flush dead end water mains all year round to prevent sediment from settling where pipes come to an end. You may experience low water pressure during flushing.

When you get a water main cleaning notice

Before water main cleaning

  • Fill a clean container with tap water for drinking and cooking
  • Complete bathing, tooth brushing, dishwashing, laundry, and other water use
  • Fill your bathtub with water for use around the house
  • Use a pail to transfer water from the bathtub to your toilet bowl to allow your toilet to flush
  • Turn water softener on bypass or shut off main water supply using the customer-owned shut-off valve, typically located next to the water meters.

During water main cleaning

  • Avoid using water as this will likely draw discoloured water into your pipes
  • Avoid washing clothes or dishes as discoloured water may cause stains

After the water main cleaning

Please run cold, unsoftened water from the tap closest to your water meter (usually in the basement) for 10 minutes.

If the water remains discoloured after 10 minutes, please turn off the tap, wait an hour, and run the tap for another 10 minutes.

Please contact us if

  • Your water does not clear after 2 hours
  • You have low water pressure or no water after water main cleaning

When your water is clear, turn on your water treatment or softener, flush other taps as needed to remove discoloured water from your pipes.

Flush your toilets as usual to remove discoloured water from your toilet tank.

Resume normal use.

Water Services
519-822-1260 extension 5627
[email protected]