Waterloo Region in September: Fewer Sales, Tighter Supply, and What a 3.8-Month Reading Means

What Cornerstone reported for September

The Cornerstone Association of REALTORS published its September 2026 statistics for Waterloo Region, and the headline is a quiet one: fewer people buying, fewer people selling, and prices drifting lower rather than falling off a ledge.

According to Cornerstone's statistics page, sales across the region were down 18.9% compared with September 2025, while new listings were down 16.7% over the same period. Measured against August, sales fell 14.2%, but newly listed properties jumped 38.4% as the autumn market opened.

Buyers and sellers in Waterloo Region continued to take a cautious approach in September.— Bill Duce, CEO, Cornerstone Association of REALTORS

Duce added that the region had the tightest supply across Cornerstone's coverage area at 3.8 months, which he read as a market that remains relatively balanced, with modest price declines despite the slowdown. Cornerstone's coverage is wider than Waterloo Region (it also reports on places such as Hamilton and Niagara North), which is why the board can call one part of it the tightest.

What "3.8 months of supply" actually measures

Months of supply is a simple idea: if no new homes were listed, how long would the current stock take to sell at the recent pace of sales? Cornerstone reported 3.8 months of supply across all property types at the end of September.

Two things can move that number, and in September they pulled in opposite directions. Fewer sales make the pile look bigger relative to demand. A smaller pile, which Cornerstone reports as inventory down 12.8% from a year earlier, makes it look smaller. The result was a figure 5.0% lower than September 2025 but higher than the 3.5 months we cited from the board's August release.

So "tight" here is relative. Cornerstone's September release does not include a ten-year average for the month, so we are not going to guess at where 3.8 sits against history. What the figure does say is that buyers have more choice than a year ago on some measures and less on others, depending on whether you look at the stock of homes or the pace of sales.

Two cities, two price indexes

The board's price index, which tracks a typical home rather than whatever happened to sell that month, tells the same story with a small twist. In Kitchener-Waterloo the MLS Home Price Index (HPI) was $630,200, up 0.3% from August but down 5.6% from a year earlier. In Cambridge it was $662,700, down 0.6% on the month and 4.1% on the year.

In August, by the figures in our earlier look, Kitchener-Waterloo was at $628,300 and Cambridge at $666,400. One month later, Kitchener-Waterloo had edged up and Cambridge had edged down, narrowing the gap between them to about $32,500. A one-month move that small is not a trend; it is worth watching, not acting on.

• Kitchener-Waterloo: $630,200, +0.3% month over month, -5.6% year over year.
• Cambridge: $662,700, -0.6% month over month, -4.1% year over year.
• Region-wide sales: -18.9% year over year; new listings -16.7%.
• Supply: 3.8 months, 5.0% lower than September 2025.

Why a lower benchmark matters to a mortgage

A falling benchmark does not change what you owe. It changes the ratio between what you owe and what the home would currently be worth, which lenders call loan-to-value, and that ratio shows up whenever a lender looks at your file.

Here is an illustration, using only the board's percentages. Take a Kitchener-Waterloo home that sat at the benchmark a year ago. Working back from a 5.6% fall, that benchmark was roughly $667,600. Someone who bought at that level with a 20% down payment borrowed about $534,100. Against today's $630,200 benchmark, and before counting a single payment of principal, that balance is roughly 85% of value rather than 80%.

That is a worked example, not a statement about any home. A benchmark is not an appraisal, your balance will have come down, and the lender's own valuation is what counts. But the direction of the arithmetic is the point. It is most relevant if you are thinking about a refinance, a home equity line or a switch to a new lender at renewal, because those are the moments a lender asks what the property is worth. A straight renewal with your current lender is a different case, which we cover in our piece on switching lenders at renewal.

If you are buying, the same softness cuts the other way: a purchase price is negotiated against comparable sales, and the lender will appraise it. Our appraisal explainer covers what happens when the two disagree.

What to do with a number like this

Regional statistics are a starting point for a conversation, not a verdict on your street. Cornerstone itself cautions that its figures help identify long-term trends but do not indicate that a specific property has gained or lost value, and points people to a local REALTOR for property-level information.

• Buying: get a pre-approval that reflects your real documents, then compare the monthly payment on several price points with our mortgage calculators.
• Renewing: check your balance and your lender's renewal timeline early; our 120-day renewal window guide sets out the sequence.
• Owning and wondering: ask for a valuation opinion before assuming your equity position from a regional index.

If you are in Kitchener, Waterloo, Cambridge or the surrounding townships, our Waterloo Region page covers how we work locally, and you can book a conversation any time.