Take Control of Your 2026 Property Taxes

If you own or occupy an industrial building anywhere in the Greater Toronto Area, you are operating in one of the tightest, most valuable industrial markets in the world, but your property taxes are still anchored to a world that no longer exists. On paper, Ontario’s property tax system remains frozen at a valuation date of January 1, 2016, while in practice many owners have continued to see tax pressure rise as municipalities lift rates and MPAC adds value through change notices and supplementary assessments.

Last year, the focus was on helping owners take control of their 2025 property taxes by paying close attention to assessment notices, value changes, and appeal deadlines. That advice remains relevant in 2026 because the valuation framework is still largely unchanged, but the cumulative exposure has grown and the risk of missing a deadline is more costly than ever.

Where the Market Stands in 2026

MPAC continues to use the January 1, 2016 valuation date for the 2026 taxation year, and a province-wide reassessment has still not been implemented. Instead, 2026 notices are being issued where there has been a change to the property, such as new construction, an addition, a renovation, a classification update, or other correction to the assessment record.

This matters for industrial owners because the absence of a broad reassessment does not mean assessed values are static. MPAC has continued to send new notices to hundreds of thousands of Ontario property owners, including commercial and industrial owners whose files were changed since their last notice. In other words, the system may look frozen from a distance, but at the property level it is still moving.

The 2026 Deadline Question 

For most commercial and industrial properties in Ontario, the annual deadline to challenge the 2026 assessment was March 31, 2026.That date applied to formal appeals to the Assessment Review Board for many business properties, and MPAC materials for the 2026 tax year also indicate that the Request for Reconsideration deadline is printed on the notice and commonly falls on March 31 for annual notices.

So, is it too late? If an owner received a standard 2026 Property Assessment Notice with a March 31, 2026 filing deadline and no Request for Reconsideration or ARB appeal was filed by that date, then for that annual assessment it is generally too late to start a new 2026 challenge. Missing the deadline does not automatically eliminate every option, but it usually closes the door on a fresh appeal of that regular annual notice.

What if the deadline was missed? 

The first step is to identify exactly which notice was missed. A standard annual assessment notice is different from a Property Assessment Change Notice, and a supplementary or omitted assessment can carry its own separate deadline, often 90 days from the notice date. Owners sometimes assume they are out of options when in reality a later-issued change notice may still be open for review.
If the March 31 deadline was missed for the annual 2026 notice, there are still several practical steps worth taking:

• Review whether any Property Assessment Change Notice, supplementary notice, or omitted assessment notice was issued later, because those notices can open a separate filing window.
• Check whether MPAC made an obvious factual error, such as incorrect building area, duplicate improvements, wrong classification, or a non-existent addition, because some clear administrative issues may still be worth raising directly with MPAC even if the formal appeal window is closed.
• Shift attention immediately to the 2027 cycle so the same property is not left unchallenged again next year.

The key point is that a missed annual deadline changes the strategy; it does not justify inaction.

Two Paths to Challenge an Assessment 

For commercial and industrial properties, owners generally have two avenues when a deadline is still open: a Request for Reconsideration with MPAC or an appeal to the Assessment Review Board

Request for Reconsideration

A Request for Reconsideration, or RfR, is the more informal route and can be useful where the issue is factual and relatively straightforward. It is often well  suited to situations involving incorrect square footage, wrong tenancy assumptions, building permit misunderstandings, or classification errors. If MPAC’s response is unsatisfactory, the owner can then appeal that result to the ARB within the prescribed follow-up timeline.

Assessment Review Board Appeal 

An ARB appeal is a more formal tribunal process and tends to make sense when the property is larger, the value at stake is significant, or the argument depends on valuation evidence rather than a simple data correction. For institutional or multi-building industrial portfolios, this route can be more effective when supported by a property tax consultant, appraiser, or legal advisor familiar with Ontario assessment practice.

Five 2026 Strategies for GTA Industrial Property Owners 

1. Track every MPAC notice across the portfolio 
The simplest reason owners lose value is because notices go unread, are sent to the wrong party, or are not escalated quickly enough internally. Every industrial owner should maintain a central tracker that captures the property, roll number, municipality, notice type, assessment year, issue date, filing deadline, and the action taken.

2. Scrutinize increases tied to permits and so called improvements
Industrial owners should pay close attention whenever MPAC attributes value to an improvement, because permits for maintenance or required repairs do not necessarily justify an increase in assessment. Our 2025 newsletter highlighted examples where assessment increases were tied to activity that did not actually support added value, including misread building permits and assumptions about changes in use.

3. Focus on equity, not just headline market value 
Because assessments remain tied to 2016 values, arguing that the property is worth less than current market pricing is often less useful than proving it is assessed unfairly relative to comparable industrial properties. Owners should compare assessed value per square foot, effective site valuation, and assumed rent levels against similar assets in the same municipality.

4. Integrate tax strategy into leasing and underwriting
Property tax should not be treated as a passive operating expense in a GTA industrial market that has changed dramatically since 2016. Tax exposure should be stress-tested in acquisition underwriting, development feasibility, and lease negotiations, especially where future reassessment could materially alter recoveries and occupancy costs.

5. Prepare now for the next assessment 
The attached 2025 newsletter warned that light industrial properties in parts of the GTA were being assessed at only a fraction of more recent sale prices, suggesting potentially sharp future assessment increases once a new valuation date is adopted. While the timing of the next broad reassessment remains uncertain, owners who organize their records, benchmark their assessments now, and challenge clear inequities today will be better positioned when the reset comes.

A Practical Example 

Consider a hypothetical GTA industrial owner with a 120,000 square foot distribution building who receives a 2026 change notice showing a material increase tied to an improvement. On review, the “improvement” turns out to be a roof replacement, sprinkler work, and life-safety upgrades that were necessary to maintain operations rather than enhance the value-generating utility of the building. In that scenario, the owner should request the underlying basis for the increase, compare the assessment against similar industrial product nearby, and determine quickly whether an RfR or ARB filing is required before the notice deadline expires.

What Owners Should Do Right Now

For landlords and owner-occupiers of GTA industrial buildings, the best immediate action plan is straightforward:

1. Pull every 2026 MPAC notice for every industrial asset in the portfolio and confirm the type of notice and deadline shown.
2. Separate regular annual notices from Property Assessment Change Notices and supplementary assessments, because they may carry different filing windows.
3. Review the property facts carefully, including building area, land size, use, occupancy, improvements, and classification.
4. Benchmark the assessment against comparable industrial buildings in the same municipality.
5. Where the dollars justify it, involve an experienced property tax consultant or advisor early rather than after the deadline has passed.

Closing Thoughts 

Industrial owners across the GTA have spent years navigating a property tax system that appears static on the surface but continues to evolve beneath it. The result is a market where many owners are underprepared for both present-day notice activity and the future reassessment shock that may eventually arrive. Even if the March 31, 2026 deadline was missed for a standard annual notice, there may still be meaningful work to do through change notices, administrative review of obvious errors, and immediate preparation for the next cycle. The owners who treat property tax as an active part of asset management rather than a back-office afterthought will be in the strongest position to protect value and avoid costly surprises.

Call to Action

If you own or occupy industrial property in the Greater Toronto Area and want to understand whether your current assessment is fair, the first step is a disciplined review of your notices, tax exposure, and comparable assessments. A portfolio-level review can help identify which assets warrant immediate attention, which missed deadlines still leave room for action, and where to focus ahead of the next reassessment cycle.