MONTREAL – About 40 homes were evacuated Tuesday morning following a water main break and gas leak in Montreal's west end Notre-Dame-de-Grâce (NDG) neighbourhood.

"We looked out on the street and the street was a river, so clearly we knew there was a water main break," said resident Chris Hosein. "We went downstairs opened up the door and we could smell the gas in the street." 

The worry, according to the Montreal fire department, is that gas may have leaked into the basements of the homes.

The water main break was on Old Orchard Avenue, near Monkland Avenue. The city's work on a nearby reservoir put extra pressure on aging pipes. When residents used less water at night, pressure built up, and they burst, according to borough manager, Stephane Plante. 

"It's very important to control the pressure in the pipes. Something happend there that made the pressure go higher, by the time they were able to monitor everything the leakage started," he said. "We have to work on replacing the old pipes and we have to intervene quickly when there is a leakage."

Firefighters had to cut water in the area to access the gas leak.

“It wasn’t due to an excavation. It was underground,” explained Montreal fire department spokesperson Louise Desrosiers. “The electricity was shut off too because of the danger of the high concentration of gas in the surrounding area.”

At the height of the outages, there were more than 8,900 homes in the dark. 

Desrosiers says she expects residents to be able to return to their homes by Tuesday evening.

“Before they will be going back into their houses, we’re going to make sure the gas leak has been taken care of,” she said, adding the goal is to undermine a risk of explosion.

“We will be taking readings in each home before we allow residents back into their homes.”