The smell is so bad, people say, it can wake you from a sound sleep, give you headaches, make you gag, even make you vomit.
The culprits are hydrogen sulphide and other gases wafting from sewer lines under repair in West Jasper Place.
"It's a sewer smell," Irene Blain, civic director for the community league, told a CBC crew Wednesday.
"But the smell that we have dealt with is a thousand times worse than that. And it happens usually between midnight and 1 a.m. on certain days."
On those nights, Blain said, the smell is so bad it wakes people up.
And they have no way to escape, she said, because they're in bed trying to sleep.
"You're like a hostage," she said. "It's terrible."
The city completed a project known as W-13 back in 2013. It's a huge underground chamber built to hold runoff after rain storms. Once it fills, it drains into the trunk lines in the sewer system.
When crews connected the trunk lines to W-13 then found that the concrete on some lines had so badly deteriorated that it had to be repaired.
The contractor hired to fix part of that trunk line started work this spring, said Siri Fernando, a sub-surface utility engineering specialist with the city.
They dug down and opened a chamber right at 151st Street and 99th Avenue, but found water levels were so high they couldn't safely finish the work.
Construction on the project was put on hold at the end of June and is slated to resume in early September, Fernando said.
The city has monitored the air in the area during the day, and found the hydrogen sulphide level has never been higher than one part per million, he said.
People can smell the gas, he said, but at those low levels it should not pose any health risks.
The work crew will now seal the underground chamber, to stop the leaking gas, and wait until September when water levels should drop, Fernando said.
"There should be a significant reduction in smell by next week."
Andrew Knack, councillor for Ward 1, said he rides his bicycle through the area every day and smells the gas.
He said some of the headaches for residents can be traced back four years, to when neighbourhood renewal started. That's when crews found problems with the sewer trunk lines.
He said the city hasn't clearly communicated with residents, so they don't have a firm idea of what's going on.
He said he hopes to soon have more information about when the sewer project can finally be finished.
Knack called the four years people have waited for the work to be completed "unacceptable," but also said the gas people smell poses no health concerns.
"I don't have a firm timeline," he said. "And that's the frustrating thing, I think, for both myself and everybody living by here. Because it's just been under construction for so long."
Steps the crews have taken to control the smell obviously haven't worked, he said.
"We're sorry," he said. "The fact that it has taken this long is completely unacceptable."
People who live nearby say whatever the city has been doing, it has taken too long and has made their lives miserable.
Blain said the nasty smell has been around since May. One night she woke up and felt like she was choking, like she couldn't get any oxygen.
She said she has spoken to neighbours who have gagged so violently they've vomited. People have developed headaches and sore throats.
"When you vomit, that's not good," she said.
This week the city installed air-quality monitors.
Jeri Loitz, who lives near ground zero for the problem, said sewer work in the area has been going on for months now.
"Rotten eggs, really sour, really potent," she said, describing the odour.
"It's hot out. So when you have all the windows open, the whole house smells like it. All day, all night. Sometimes you can't sleep because it smells terrible. It wakes you up."
Loitz said she plans to call the city to complain.