2026 property taxes are still based on January 1, 2016 current values. No province-wide reassessment has been announced (MPAC, the assessment cycle). What changes year to year, and what actually forces a decision, are the deadlines below.
MPAC does not reassess every property each year. Outside of a general reassessment, it mails a new notice only when something changes, for example new construction, an ownership transfer or a change in use; in its most recent round that meant more than 618,000 properties received one (MPAC, notice mailing). For every other property, the assessed value carries over and the same annual deadlines apply.
Last checked: September 2026. This page is reviewed each year as MPAC and the Board confirm new dates.
| When | What it means | Who it affects |
|---|---|---|
| March 31 | Deadline to appeal the current year’s annual assessment to the Assessment Review Board, or to file a Request for Reconsideration with MPAC. Business properties may go straight to the Board. | Every commercial, industrial and multi-residential owner |
| 120 days after a notice | Deadline to appeal a change, amended, supplementary or omitted notice | Owners who built, renovated, severed or changed the use of a property |
| 90 days after an RfR decision | Deadline to appeal MPAC’s Request for Reconsideration decision to the Board | Owners who filed an RfR and disagree with the result |
| May 27 to July 22, 2026 | MPAC’s Property Income and Expense Return (PIER) mailed and due | Owners of rented commercial, industrial and multi-residential buildings |
| February 28, 2027 | Deadline for a section 357 or 358 application to cancel, reduce or refund 2026 taxes, for example for a building that was damaged, demolished or unusable | Owners with a fire, demolition, flood or long vacancy in 2026 |
| September 30, 2027 | Deadline for council to decide a section 357 or 358 application made for the 2026 tax year | Owners waiting on a 2026 tax adjustment application |
| Through the year | Change notices and omitted or supplementary assessments whenever MPAC completes a review of new construction or an addition | Developers and owners after construction |
March 31
March 31 is the deadline to appeal the current tax year’s annual assessment to the Assessment Review Board, or to file a Request for Reconsideration with MPAC (Tribunals Ontario, filing an appeal). Commercial, industrial, multi-residential and other business properties are not required to file an RfR first and can appeal directly to the Board by this date. See RfR or straight to the Board for which route fits.
120 days after a notice
MPAC issues notices outside the annual cycle when something about a specific property changes: new construction, a demolition, a severance, or a change in use, among others. A change, amended, supplementary or omitted notice carries its own 120-day appeal window from the date on the notice, separate from the March 31 date (Tribunals Ontario).
90 days after an RfR decision
If you filed a Request for Reconsideration, MPAC aims to respond within 180 days. Once it mails its decision, you have 90 days to appeal that decision to the Assessment Review Board if you disagree (MPAC, Request for Reconsideration and Appeals).
The Property Income and Expense Return (PIER)
Each spring, MPAC mails PIER requests to owners of income-producing commercial, industrial and multi-residential properties, collecting rent, vacancy and expense information for the previous year. In 2026, MPAC mailed requests on May 27, due July 22. Filing is mandatory under section 11 of the Assessment Act (MPAC, Property Income and Expense Return). See our PIER service.
Section 357 and 358: February 28 of the following year
Sections 357 and 358 of the Municipal Act, 2001 let a municipality cancel, reduce or refund taxes for reasons such as a building that became unusable through damage or demolition, a change in use, or an assessment or classification error (MPAC, filing for a property tax adjustment with your municipality). The application deadline is the last day of February of the year following the tax year in question; for 2026 taxes, that is February 28, 2027 (City of Greater Sudbury, section 357/358 applications). See tax refunds and rebates.
Council’s decision: September 30
Once a section 357 or 358 application is filed, council must give its decision by September 30 of that following year under the Municipal Act, 2001 (Ontario, Municipal Act, 2001). For a 2026 tax year application, that is September 30, 2027.
Through the year: notices after construction
Outside of the fixed dates above, MPAC issues a change notice, or an omitted or supplementary assessment, whenever it finishes reviewing a new building, an addition or another change on a property. Each of these carries its own 120-day appeal window from the date on the notice, which is why the date printed on a specific notice always takes priority over a general assumption about when a deadline falls for your property.
None of these dates move for a slow year or a busy one. If you are not sure which deadline applies to your notice or your property, see how an assessment appeal works, RfR or straight to the Board for which route to take, or contact us before the date passes.