Montreal city officials knew the major water main that burst last week was showing signs of damage, but thought there was still time before it needed to be repaired, the head of the city’s water service said Monday.
Chantal Morissette told reporters the city noticed the pipe was deteriorating during an inspection in 2017 or 2018. She said a followup inspection was planned in the coming months.
“But the pipe burst before we arrived, so the corrosion was more advanced than what we suspected during the investigation,” she said.
Montreal Mayor Valérie Plante said 50 buildings were flooded when millions of litres of water erupted onto city streets on Friday, and 16 households have asked the Red Cross for emergency housing.
She said workers are now removing debris from roads in the area, but it will take time to assess exactly what happened and order the parts to repair the two-metre-wide pipe.
Plante said she’s relieved the city didn’t have to shut off the drinking water supply to any customers, although Montreal did issue a boil-water advisory for about 150,000 homes for more than a day.
The pipe involved in Friday’s water main break was a C301 pre-stressed concrete pressure pipe, which consists of a steel cylinder embedded in concrete and reinforced with steel wire. Morissette said corrosion, possibly caused by water accumulation or road salt, can break the steel wires and eventually cause such pipes to explode.
In theory, water main pipes can last for 100 years, but C301 pipes have a shorter lifespan than those built earlier in the 20th century, Morissette said. The pipe that burst on Friday had been installed in 1985.
Despite this latest incident, Morissette said, recent investments have cut the number of water main breaks in Montreal by 50 per cent in the last 12 years. She said 90 per cent of the city’s network is in good shape.
There’s no timeline on when the repairs will be finished.
Meanwhile, Plante gave an update on the damage caused by torrential rain that hit Montreal on Aug. 9, saying more than 3,300 private buildings and about 60 municipal buildings were flooded.
