Why perform maintenance on the waterworks system?

Last updated August 8, 2022
Reading time: 2 min

There are more than 9,000 kilometres of water and sewer mains running underneath Montréal  —  equivalent to the distance between Montréal and Edmonton, Alberta! This massive network must be maintained and repaired to ensure its quality, efficiency and sustainability.

Our water system at a glance

The waterworks system is composed of two separate networks, each of which has its distinctive role to play. The drinking water system distributes drinking water to homes, businesses, factories, hospitals and fire hydrants. The sewer system collects wastewater, routing it to treatment plants and diverting storm water to avoid backups in buildings and overflows onto streets.

Each of these networks is composed of main lines, which have larger diameters, and secondary lines, which have smaller diameters. Main lines, or mains, usually run underneath major streets. The waterworks system routes clean water from filtration stations to reservoirs and the secondary network which serves the population. Wastewater takes a reverse path through the sewer network, leaving buildings through the secondary network, which routes them to mains on the main network and onward to the Jean R. Marcotte treatment station on the eastern tip of the island of Montréal.

What kind of work needs to be done?

Just like houses, waterworks need maintenance work to avoid major and costly, unexpected repairs. Prevention includes:

  • Annual inspection of fire hydrants
  • Inspecting valves and valve chambers
  • Leak detection
  • Using a camera to check the condition of sewer mains
  • Cleaning sewer mains and drains

Maintenance work is done regularly and systematically so we can see the actual condition of the system, plan which action to take and inform users in advance. As needed, work is done to: 

  1. Repair mains: When water or sewer mains reach the end of their lifespan, we line the pipes, which extends their useful life. Pipe lining is economical, ecological and fast. Only a few weeks are needed to perform the work.
  2. Replace mains: When mains are in poorer condition, they may need to be replaced with new pipes. This means completely opening the road. Several months may be needed to complete the work.

Did you know?

Before 2000, there was a maintenance deficit in Montréal’s water system, leading to a backlog of repairs to be performed. Since then, several hundreds of millions of dollars are being invested each year in water main replacement and maintenance to keep the system in good working order and absorb the deficit.