A new report warns Canada's housing market is reaching the limits of sustainability and could tumble if there is no moderation.

The Bank of Montreal's followup on its November analysis finds that Canada's hot housing market is still not in the red zone for prices, but it's close.

The bank notes that after slowing last summer, Canadian home sales rebounded in the fall and house prices have kept rising. On average, home prices rose five per cent in the past year to January, while in Vancouver they rocketed 20 per cent.

Incomes, however, have not increased nearly as fast.

How much the price-income ratio exceeded the long-term trend in 2010
Saskatchewan 39%
Newfoundland 34%
British Columbia 31%
Manitoba 31% 
Quebec  23% 
Ontario  10% 

The bank says the ratio between average resale prices and personal incomes nationally is 14 per cent above the long-run trend, up from last summer, but still below the 21 per cent peak that preceded the 1989 crash.

But that is not the case in all markets. Five provinces are currently in the danger zone, led by Saskatchewan, where the ratio is 39 per cent above historic norms.

Also well-above the long-run levels is Newfoundland, 34 per cent higher; British Columbia and Manitoba, 31 per cent, and Quebec, 23 per cent above.

By comparison, in Ontario the price-to-income ratio is only 10 per cent higher than historic norms, suggesting prices are moderately overvalued but not in bubble territory.

220-toronto-condos-construc

Condos are seen being built in Toronto. A closely watched ratio of prices to income is currently 10 per cent higher than normal in Ontario. (Chris Roussakis/Canadian Press)

The bank says there should be no major correction if going forward price increases stay in line with income growth.

It says sales are indeed expected to cool and prices stabilize this year in response to higher interest rates and tighter mortgage rules that go into effect later this month.

If prices don't stabilize, however, the report says it would put the Bank of Canada in a tight spot. It risks creating a housing bubble if it keeps rates super-low too long, or could precipitate a crash if it hikes rates too quickly.