In short · September 28, 2026
In Ontario, a Request for Reconsideration must be filed by March 31 of the tax year (Assessment Act, s. 39.1 (1.1)), or within 120 days of the issue date on a Property Assessment Change Notice, and for 2026 the value under review is still the one as of January 1, 2016.
The general rule: March 31
The Assessment Act is clear: a Request for Reconsideration "must be made no later than March 31 of the taxation year in respect of which the request is made" (s. 39.1 (1.1)). Each tax year has its own deadline. MPAC confirmed March 31, 2026 for the 2026 tax year.
MPAC adds that each year's deadline is printed on your notice. Rely on that date: in 2024, March 31 fell on a Sunday, and MPAC announced April 2, 2024 as the deadline.
The exception: 120 days after a change notice
MPAC sends a Property Assessment Change Notice (PACN) during the year when a property changes: an addition, new construction, a renovation, a structure assessed for the first time, a change in classification. The Act calls these supplementary or omitted assessments (s. 35 (1)).
For that notice, the deadline is 120 days "after the issuance date on the notice of assessment" (s. 39.1 (3)). MPAC's PACN sheet puts it simply: "Property owners will have 120 days from the Issue Date on their PACN to file a RfR." The issue date and your own deadline are printed on the notice.
Keep the logic straight: March 31 is everyone's rule, and 120 days is the rule for someone who received a change notice. You do not get to pick the later one.
The deadlines at a glance
Deadlines that apply to a residential owner, according to the Assessment Act and the Assessment Review Board:
| Situation | Deadline | Source |
|---|---|---|
| Request for Reconsideration, general case | March 31 of the tax year | Act, s. 39.1 (1.1) |
| Request for Reconsideration after a change notice (PACN) | 120 days from the issue date | Act, s. 39.1 (3) |
| First year of a general reassessment | 120 days from the issue date on the notice | Act, s. 39.1 (1.2) |
| MPAC’s response | 180 days (240 with a notified extension) | Act, s. 39.1 (7) |
| Appeal to the ARB after the decision | 90 days from the issue date of the decision | Act, s. 40 (5) |
Why values still date from 2016
Normally, Ontario reassesses every property every four years. Section 19.2 of the Act provides that for 2017 to 2020, "land is valued as of January 1, 2016." In 2016, MPAC mailed a notice to every property owner in the province.
The next update never happened. MPAC sums it up: "the Ontario government has postponed the 2020 Assessment Update," because of the pandemic. On August 16, 2023, a regulation extended the postponement through the end of the 2021-2024 cycle. Today, O. Reg. 282/98 (s. 48.6) prescribes January 1, 2016 for the 2021 to 2026 tax years.
What about 2027? As of September 28, 2026, the regulation goes no further than 2026, and no official source we consulted says which date 2027 assessments will use. Watch mpac.ca and your notice. If a general reassessment happens, the Act sets a 120-day deadline from the notice's issue date for its first year (s. 39.1 (1.2)).
What 2016 means for your file
MPAC puts it this way: the 2026 assessment is what the property "would have sold for on January 1, 2016 – in its current state and condition." The market is frozen in 2016, while the property is taken as it stands today, including major changes made since.
The consequence: a 2025 sale on your street proves little. Useful sales are the ones close to January 1, 2016, adjusted as needed. See evidence that works. It also explains why your assessment often looks far from market price: see municipal assessment vs market value.
Phase-in no longer plays a role. After 2016, an increase was spread in four equal steps from 2017 to 2020, and a decrease applied right away. In 2026, values are "fully phased-in."
Official sources
- Assessment Act, R.S.O. 1990, c. A.31 (e-Laws, Ontario)
- O. Reg. 282/98 (General), art./s. 48.6 : date d'évaluation 2021-2026 (e-Laws)
- MPAC : The Assessment Cycle
- MPAC : Notices and Notifications
- MPAC : Property Assessment Change Notice, fiche 2022 (PDF)
- MPAC : How Phase In works
- Tribunals Ontario, ARB : Filing an Appeal
- MPAC : How to file a Request for Reconsideration (RfR)
Talk to a professional appraiser in your area
For an income property, a high value or a file headed to the appeal board, a professional appraiser (AACI or CRA) is the right person. Payotte has verified 42 in Ontario, one per sector, selected on public data, never on their budget.
Find the verified appraiser in my areaGeneral information based on public sources. This is neither legal advice nor a certified appraisal. A review request can also lead to a higher value.
Frequently asked questions
How long do I have to file a Request for Reconsideration in Ontario?
Until March 31 of the tax year (Assessment Act, s. 39.1 (1.1)). The exact deadline is printed on your notice. After a Property Assessment Change Notice, it is 120 days from its issue date.
Can I choose between March 31 and 120 days?
No. March 31 is the general rule. The 120 days apply to someone who received a Property Assessment Change Notice, counted from the issue date printed on that notice.
Will 2027 assessments still be based on 2016?
No official source says so as of September 28, 2026. O. Reg. 282/98 prescribes January 1, 2016 only through the 2026 tax year.
What is the deadline to appeal to the ARB?
90 days from the issue date of MPAC's decision on your Request for Reconsideration (Assessment Act, s. 40 (5)). If MPAC did not respond on time, 90 days from the date it should have.