On October 16, CMHC's September housing starts release produced a striking Ontario number: actual starts in centres of 10,000 or more fell 46% from September 2025, from 7,465 to 4,054. Multi-unit starts, which include rental and condo apartments, were down 55%, from 6,597 to 2,994.[1]

Numbers like that make headlines. Before treating them as a turning point, it helps to look at what they're being compared with, and at the parts of the release that say more about future supply.

Nationally, the picture was milder. Actual starts in centres of 10,000 or more fell 11% from September 2025, while the seasonally adjusted annual rate rose 3% from August to 248,896 units. The number of units under construction in larger centres was flat at 371,617.[1]

Look at the comparison month

Monthly starts are lumpy. A single large apartment project can add hundreds or thousands of units in the month construction begins. When the comparison month had several of those, the year-over-year change will look dramatic even if activity is steady.

The September data shows this clearly in Ontario's mid-sized cities:[1]

  • London had 223 starts in September, down 80% from 1,102 a year earlier. But London's starts for January to September were 3,085, up 28% from 2,403.
  • Kitchener-Cambridge-Waterloo had 112 starts, down 91% from 1,259. Its year-to-date total was down 17%, a real decline but much smaller than the monthly number.
  • Ottawa went the other way, with 914 starts, up 93% from 474, and a year-to-date total up 14%.

In London and Kitchener-Waterloo, September 2025 included a lot of multi-unit starts. In London, multi-unit starts were 1,054 in September 2025 and 155 this year.[1] A comparison with that month says more about last year than about this one.

Year-to-date is the better gauge

For Ontario as a whole, actual starts from January to September were 43,994, down 5% from 46,111 in the same period of 2025. Multi-unit starts were down 6% and single-detached starts were up 1%.[1]

The picture by city over nine months is varied:[1]

  • Toronto: 17,397, down 14%.
  • Hamilton: 1,253, down 39%.
  • Ottawa: 8,168, up 14%.
  • London: 3,085, up 28%.
  • St. Catharines-Niagara: 1,813, up 21%.

That's a province with weak spots, especially Toronto and Hamilton, not one where construction stopped in September.

CMHC's own trend measure, a six-month moving average of seasonally adjusted annual rates, was virtually flat nationally at about 250,000 units. In Toronto, CMHC said the trend was flat as single-detached and multi-unit trends offset each other.[1]

The pipeline tells you about the next two years

For rental owners, starts matter mainly as a signal of supply in two to four years. Three other parts of the release say more about the nearer term:[1]

  • Units under construction. In Ontario centres of 50,000 or more, 145,608 units were under construction in September, down 2.5% from August. In Toronto, the figure was 88,108, down 3.8%.
  • Completions. Ontario completions rose 16.4% to 6,871 in September. Toronto completions roughly doubled, to 4,766.
  • Approved units not yet started. Ontario had 34,448 units with building permits that hadn't started construction, up 7.6% from August. London's count rose 39% to 2,644, and Kitchener-Waterloo's 78% to 1,250.

Put together, these show a pipeline that is still delivering a lot of new units now, a slowly shrinking stock under construction, and a growing backlog of permitted projects waiting to start.

What the backlog could mean

The rise in approved-but-not-started units is the number worth watching. It could mean several things:

  1. Projects waiting for better conditions. Developers with permits may be holding off until costs, rates or rents improve.
  2. Projects timed to incentives. Municipal development charge reductions and federal financing programs can encourage developers to secure permits early and start later.
  3. Projects that won't proceed. Some permitted projects never start.

The release doesn't say which applies. But a growing backlog means starts could rebound quickly if conditions improve, or remain low if those projects stall.

The takeaway

One month of starts data is a weak signal, especially when the comparison month was unusually strong. For Ontario rental, the more useful readings from the September release are a 5% year-to-date decline, high completions that will keep lease-up competitive in the near term, and a growing stock of permitted projects that will decide how much supply arrives in 2028 and beyond.

Sources

[1] Housing starts and other construction data, September 2026, CMHC (Oct. 16, 2026): https://www.cmhc-schl.gc.ca/media-newsroom/news-releases/2026/housing-starts-construction-data-september-2026