Watermains

Watermains are underground pipes that deliver a steady supply of fresh, clean drinking water to residents and businesses.

Fast Facts

  • There are more than 6,000 km of watermains in the City’s water distribution system.
  • Most watermains are metallic (made of cast iron or ductile iron).
  • The average age of Toronto’s watermains is 59 years:
    • 13 per cent are 80-100 years of age
    • 11 per cent are more than 100 years old
  • Watermain pipes are buried about 1.8 m deep, just below the the frost line.
  • The City experiences an average of 1,400 watermain breaks annually.

  • Watermains break more frequently in winter months – November to March – because low temperatures can cause soil to freeze and expand, creating frost loading or force applied to a watermain.
  • External corrosion can cause pits to develop in cast or ductile iron pipes, weakening them over time.
  • Smaller cast iron watermains constructed in the 1950s/60s are more prone to break as they have thinner walls.
  • Leaks can also erode the ground or ‘bedding’ surrounding a watermain, ultimately causing the pipe to collapse.
  • North York, Scarborough and Etobicoke experience the highest break rates as their watermains are located in predominantly acidic clay soil as opposed to sandy soil.

The City is improving the watermain distribution system through the following programs:

Watermain Replacement

The City replaces approximately 35 to 50 km of watermains each year.

A combination of factors are considered when prioritizing replacement, including: pipe age and material, break frequency, operational performance, future growth, and coordination with other construction projects (i.e. gas, hydro) in order to minimize cost and disruption to the community.

Watermain Rehabilitation

The City rehabilitates more than 130 km of watermains each year to help extend the life of its watermains. This is done through the following methods:

Cathodic Protection

  • Involves attaching anodes (magnesium cylinder) to an existing watermain, which then corrode instead of the watermain itself.

Structural Lining

  • Fibreglass is inserted within an existing watermain to form a new pipe wall.
  • Best suited when larger diameter watermains need to be renewed and the cost of open-cut (trenching) and traffic disruptions are significant.

Residents should call 311 to report a watermain break. Toronto Water staff are available 24 hours a day, seven days a week to respond to calls. Depending on the severity of the break, repairs can take up to 24 hours and sometimes longer.

Steps to Repair

  1. Staff will determine the location and severity of the break, and, if required, turn off the flow of water.
  2. Staff will acquire underground location of utilities (i.e. Enbridge, Hydro) to ensure excavation can take place safely.
  3. A clamp will be used to fix the hole or staff will replace the deteriorated section of pipe.
  4. Temporary road repairs will take an additional one to two days.
  5. Permanent road repairs will become part of the City’s long-term capital coordination projects.

The City flushes watermains to help clean out mineral deposits and sediment that have built up over time.