Water main and sewer cleaning

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Water main cleaning

Maintenance sometimes causes discoloured water

We recommend you wait until water is clear before using it for drinking or cooking.

Discoloured water is usually temporary. It can happen when the natural minerals in Guelph’s groundwater mix with chlorine to form small rust particles. These particles settle on the bottom of our pipes. When we clean water mains and test fire hydrants we stir up and remove that sediment, and your water may appear discoloured for a short period of time.

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 internal stop and waste valve

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 your garden hose uses unsoftened water, you can water your lawn or garden.

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 including drinking the water and clothes washing.

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.

Fire hydrant testing

The City tests over 2,700 fire hydrants throughout the year to make sure they are in proper working order in the event of an emergency. There is no disruption to water service during testing, and no chemicals are used.

Health concerns?

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. The most common element in discoloured water is iron, a nutrient found in many foods. For customers with iron storage disorders, additional iron in drinking water could present a health risk. These individuals should avoid drinking discoloured water and consult their physicians for additional information.

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.

For more information about water main cleaning and hydrant testing

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

Sewer cleaning

The City cleans sewer pipes Monday to Friday between 7 a.m. and 5 p.m., all year round. It takes a few hours on each street, and we do each street about every three years.

You will see signs on your street before we clean the sewers in your neighbourhood.

During sewer cleaning

You can use toilets, sinks and other appliances but keep toilet lids closed, and sink drains plugged when not in use. Air pressure in the sewer may cause water to splash out through toilets, sinks and drains.

Sewer cleaning can sometimes create noise or short-term nuisance odours. If this happens, open your windows and run water in your sink, shower and bathtubs, flush toilets, and pour a pail of water into basement floor drains. If the odours persist, please contact us.

How we clean sewers

We don’t use chemicals; we use high-pressure water to loosen debris and flush pipes. Then a high-powered vacuum removes debris from the pipe, and we take the debris to the wastewater treatment plant for processing and disposal.

For more information about sewer cleaning

Monday to Friday 8 a.m. to 4 p.m.
[email protected]