Canada's national housing agency says nine of Canada's 15 largest housing markets are showing signs of being overvalued.

The Canada Mortgage and Housing Corporation said in its quarterly Housing Market Assessment Wednesday that a majority of Canada's large housing markets are showing either "moderate" or "strong" evidence of being overvalued.

The housing agency looks at housing markets to gauge their health based on four factors:

overheating — when demand is significantly and persistently outpacing supply

overvalued — when prices are higher than they should be based on economic fundamentals

accelerating — when house prices are increasing faster than household costs of living are

overbuilding — when supply of new homes significantly outpaces demand.

The agency rates each market on a colour coded scale where green means there is little evidence of that factor, yellow means there is moderate evidence of it and red means there is strong evidence of it.

On the overvaluation front, the CMHC says there is moderate or strong evidence of that happening in Vancouver, Edmonton, Calgary, Saskatoon, Regina, Hamilton, Toronto, Montreal and Quebec City.

Four of those cities — Toronto, Quebec City, Vancouver and Saskatoon — now show "strong" signs of overvaluation.

The first two were singled out in the agency's last report on housing in January. But the latter two were only recently given their red warning on overvaluation.

In Vancouver's case, the housing agency said "Single-detached home prices are now observed to be at levels higher than those consistent with financial, economic and demographic fundamentals."

But the problem in Saskatoon, meanwhile, is tied to recent downward revisions to the area's population, which makes it harder to justify. House prices in the greater Saskatoon area declined 2.7 per cent in March, data from the Canadian Real Estate Association showed.

Across the country, Canada's housing market set a record last month both in terms of prices — now up to $508,567, on average — and the volume of sales, CREA said.

Aside from overvaluation in pockets, the CMHC's assessment sees little cause for concern nationally. "Overheating and acceleration in house prices are not a concern at this time," the CMHC said.