Calgary city staff will look into the controversial issue of illegal suites, which are typically found in basements in neighbourhoods where zoning only allows one family per house.

A single vote Monday passed a motion asking administrators to draw up an outline for a research study that would review the estimated 50,000 illegal suites.

"I guess my concern is, simply by acknowledging illegal suites are present, we're condoning an illegal act," said Ald. Gord Lowe.

The sponsor of the motion, Ald. Diane Colley-Urquhart, said she was surprised it passed.

"On the one hand, if you start clamping down on these illegal suites you could put people out on the street, which isn't what we want to do. But at the same time, we know people are damn well breaking the law," she said.

Council will decide in November if it'll proceed with the study.

In the meantime, city officials will continue to enforce bylaws against illegal suites only if they get complaints about them.

Calgary landlord Garth Chapman said the city should abandon its current rules regarding illegal suites in favour of ensuring secondary suites are safe, affordable and available to those that need them.

The Canadian Mortgage and Housing Corp. says the city's vacancy rate likely hovers at about 0.6 per cent, with the average two-bedroom apartment renting for $1,010 a month.