Ontario Buying · Property Tax

Is Your MPAC Assessment Actually Accurate? What Every Buyer Must Know

Assessed Value vs. Market Value · Arthur Zhao · 416-888-6161

The Municipal Property Assessment Corporation (MPAC) is a not-for-profit organization established under Ontario law. Its sole mandate is to assess the value of all approximately 5.6 million properties in the province, producing a Current Value Assessment (CVA) that municipalities use to calculate property tax bills.

The formula is straightforward: Property Tax = CVA × Municipal Tax Rate. The CVA is not designed to tell you what a property is worth in today’s open market — that’s a job for comparable sales analysis.

Here’s the fact that surprises almost every buyer I work with: Ontario’s assessment cycle was supposed to update every four years. The last full reassessment completed used a valuation date of January 1, 2016. The subsequent cycle was delayed — first for technical reasons, then compounded by the pandemic — and as of 2026, no new province-wide reassessment has been completed.

This means your neighbour’s property, your target home, every residential property in Ontario is still assessed against market conditions from a decade ago. In those ten years, Greater Toronto Area home prices rose dramatically, then partially corrected. The MPAC number captures none of that movement.

The gap between MPAC CVA and actual market value varies widely by property type and location, but in most GTA communities the divergence is significant. A Mississauga detached home assessed at $760,000 by MPAC might easily trade above $1.1 million. Conversely, in a market correction scenario, a property that MPAC assessed at $900,000 might actually sell for $820,000 — making the MPAC number appear inflated.

Neither situation means the seller is wrong, the buyer is being deceived, or the market is broken. It simply means MPAC and market value are measuring different things at different points in time.

Arthur’s Rule: Use CMA, Not MPAC, for Pricing Decisions

Some buyers use a low MPAC assessment to justify offering significantly below asking price, expecting the seller to accept because “MPAC says it’s only worth X.” Sellers in competitive markets won’t entertain this logic, and listing agents will immediately recognize it as a misunderstanding. You risk looking uninformed and damaging your negotiating position before the conversation even begins.

The same trap works in reverse: don’t assume a property is overpriced just because MPAC’s number is lower than the list price. In most GTA markets, that’s the normal relationship.

How to Properly Use MPAC Data as a Buyer

If you own a property and believe the MPAC CVA is inflated — causing you to overpay property tax — you have two formal options:

Request for Reconsideration (RfR)
File directly with MPAC. This process is completely free. The deadline for residential properties is typically March 31 of the tax year (for 2026, the deadline was March 30, 2026). MPAC will review your assessment and respond in writing within 180 days, with up to an additional 60 days if needed.

Assessment Review Board (ARB)
If MPAC’s RfR decision doesn’t satisfy you, you have 90 days from that decision to appeal to the ARB, an independent tribunal. For residential properties, you must complete the RfR step first before ARB will accept your appeal.

2026 Assessment Update

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