There were days when David Kralik would arrive at his landscaping and snow-removal business in Mississauga and stay just a few minutes – the heady odour of marijuana from the grow-op next door was too powerful.

"You open the door to come in, go into my office, and I just sit down, fire up the computer and – " He lets out an expletive. "And you just leave. It's that bad."

Mr. Kralik couldn't call the police to complain about the grow-op, or another in the same building, because they're both legal and under federal jurisdiction.

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Across the country, the operators of private but legal medical marijuana grow-ops have drawn the ire of their neighbours. Mr. Kralik says he may have to move out if things don't improve; others have complained that living or working next to a grow-op has negatively affected their business and property values.

But they could soon enjoy clean air again as the days of private medical marijuana grow-ops could be numbered.

A federal court in British Columbia is hearing a case that could shut down all private growers. The federal government replaced this method of growing with large commercial operations in 2013 and 2014, but a court injunction has allowed the small-scale producers to continue. The growers, who have licences from Health Canada to produce marijuana for their own medical consumption, have argued that the pot they produce is much cheaper than what they'd pay commercially. While neighbours to the four GTA grow-ops The Globe and Mail looked at said they don't have a problem with them in principle, they would prefer that they were housed in rural or industrial areas.

The ruling in the federal case – in which four B.C. residents allege their constitutional rights were violated by the federal government when the personal-use grow-op program was shut down – isn't due until the end of the year. Until then, neighbours to private grow-ops are seeking other ways to deal with these federally regulated facilities. Last week Mississauga City Council passed a bylaw that makes it the first municipality in Canada to give city officers powers to police private growers to some extent, a model that other GTA municipalities are considering replicating.

Reto Guenter, whose auto-body shop is in the same building as Mr. Kralik's and the two grow-ops, says he has no issues with the growers, whom he has met. He said the smell does come into his shop occasionally, though, and believes the growers need a new ventilation system to keep the smell from leaving their units.

"Do people come in and say, 'Did a skunk blow up in here?' Well, yeah," Mr. Guenter said.

But the smell may soon disappear if the growers don't comply with the new bylaw in Mississauga. The bylaw requires those who operate medical-marijuana grow-ops to obtain a $250 licence (which comes with an annual renewal fee of $200). An inspection by the city's fire department and electrical safety authority are part of the licensing process. Officials are aware of two private grow-ops in the city – the two in Mr. Kralik's building. Across Ontario, 6,077 individuals were granted licences to produce medical marijuana for themselves or for someone who needs it, according to Health Canada data from March, 2014, when the program stopped issuing licences.

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Mississauga city staff have sent notices to the two growers in town informing them about the municipal licence. If they fail to get one, the city will take legal action, said Mickey Frost, director of enforcement. The growers and the property manager for the building in which they operate could not be reached for comment.

Placing municipal scrutiny on private grow-ops is a step Vaughan Councillor Sandra Yeung Racco hopes her city will soon adopt. She didn't know a medical marijuana grow-op was operating in her ward until a resident, whose business is next door to it, made a complaint about the smell. Police and fire officials have checked out the space and an investigation by city staff is "ongoing," Ms. Yeung Racco said.

"We at least should know where they set up these units," she said. "It's better that we know and have some sort of regulation rather than having people just setting it up anywhere."

Mario Bottoni, who complained about the Vaughan grow-op, says he has lost business and has had to run his maintenance company for the last three months out of alternate locations because the smell is so overpowering. He said one of his employees has refused to come in due to the smell, and he himself can only stand it for about 30 seconds, even when wearing a mask.

A reporter who visited the site last week spoke to two employees who work at another business beside the grow-op, both of whom said they had smelled marijuana in their unit before, but only on occasion and in certain parts of the unit. The reporter could not detect the odour on that day.

The building's property manager, Rocco Rampino, said after receiving complaints about the smell, he asked the owner of the unit (who rents the space out to a grower) to improve the ventilation system, which he says has been done. An attempt to contact the grower was unsuccessful.

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For Paul Calandra, parliamentary secretary to the Prime Minister, no municipal intervention should be necessary to set residents at ease – he hopes the federal court case will permanently shut down all private grow-ops in the country. He says the overwhelming volume of applications for commercial production suggest prices will eventually come down for pot from large-scale growers.

"I certainly have no patience or tolerance for people who will suggest we need to expand residential grow-ops," Mr. Calandra said. "I think this will obviously be an election issue."

He's taken a particular interest in the issue because a residential grow-op in his Oak Ridges-Markham riding is located across the street from an elementary school. On a recent weekday afternoon as school let out, the smell of marijuana hung in the air a few blocks away and was especially pungent on the street where the house was located. The Globe was unsuccessful in reaching the grower.

Bric Williams says for the last two years since the house was built, his children's clothes have had the smell of pot baked into them – they attend the school. The pungent smell permeates his car's interior, just in the few minutes he idles outside when he picks his kids up.

"In the summertime, you have your windows open and your vehicle reeks," he said. "I'm sure if I drove away from here and got caught for speeding or something, the cop would think that I was smoking in the car."

Last month, Mr. Calandra held an open house at the school to discuss the issue. Frustrated parents and neighbours aired their grievances about the smell and associated health concerns, Mr. Calandra said, but he tried to help them understand "not to confront [the homeowner]. He's doing what he's allowed to do."