How property assessment works
In 1998, responsibility for property assessment was transferred to the Municipal Property Assessment Corporation (MPAC). This not-for-profit corporation created by the Province delivers a broad range of assessment services to municipalities, all of which are members of the Corporation. MPAC is responsible for assessing all property in Ontario. These values are provided to municipalities on annual assessment rolls. Municipalities and the Province use these values when they calculate property taxes and education taxes.
Property assessment cycle
Every four years, MPAC conducts a province-wide reassessment. All property owners are sent a Property Assessment Notice (PAN).
For the 2017 through 2020 taxation years inclusive, the effective valuation date is January 1, 2016, with any market increases in assessment being phased in over this four-year period, while assessment reductions are realized immediately. All property owners would have received a PAN from MPAC in 2016 reflecting their property’s assessed value and classification.
The next property valuation update, known as a reassessment, had been scheduled to be completed MPAC in 2020 for the 2021-2024 taxation years. As a result, MPAC would have issued new assessments for more than five million properties. To provide continued stability, the Government of Ontario had postponed the reassessment in 2020 and is implementing a further postponement of the property tax reassessment into 2023. This means that your property taxes for the 2022 and 2023 taxation years will continue to be based on the fully phased-in January 1, 2016 valuation (same as the 2021 taxation year), unless there have been changes at your property.
How assessment is determined
MPAC continually collects information about properties to ensure that those with similar features (age, living area, lot dimensions, location, construction, etc.) have similar assessed values. MPAC also analyzes real estate market information from similar types of property in your area to establish your property's value. This method - current value assessment - is used by assessment jurisdictions in most provinces as well as by other countries. The Assessment Act requires that your property's assessed value be based on what it would likely have sold for on a specific date.
Property Assessment Notice (PAN)
By the end of 2016, the Municipal Property Assessment Corporation (MPAC) will have issued assessment notices to all property owners in Ontario representing property values as of January 1, 2016. The notice also indicated the respective phased-in assessment values for the tax years 2017 to 2020 inclusive, as applicable.
In November of any given tax year, MPAC also issues notices to taxpayers in situations involving:
- A change in ownership
- A change in school support
- A change in value as a result of a property taxpayer Request for Reconsideration of an assessment or an Assessment Review Board (ARB) decision
- A change in the property that will either increase or decrease its value; such as an addition
- A new structure built
- Additional information found that affected the value of the property
Supplementary and omitted assessments
A supplementary assessment is an additional assessment (increase in value) resulting from property improvements or changes, which were not reflected in the property tax bill for the current year and occurred after the return of the assessment roll. If you are planning to build a new home or to make an improvement to your property, you should know about supplementary assessment and the resultant property taxes billed on such assessments.
A supplementary assessment can be processed for the following reasons:
- There is an increase in property value because of a new building or improvement
- A property ceases to be exempt from taxation or ceases to be eligible for assessment at the farm, managed forest, or conservation land classes
- A property ceases to be classified in a subclass of real property, farmlands awaiting development, commercial or industrial vacant land
- A property becomes liable for taxation in a different property class
An omitted assessment is an additional assessment resulting from building a new structure (i.e. home) or addition, which was not previously recorded on the annual assessment roll. An omitted assessment can be processed for the current tax year and two preceding tax years for the following reasons:
- There is an increase in property value because of a new building or improvement
- To assess and classify land that was previously exempt
- A property ceases to be classified as managed forest or conservation land
How supplementary and omitted assessments affect your property taxes
When the City issues a building permit, there will most likely be a value change in the property, which creates a supplementary/omitted assessment. Your property assessment will need to be updated to reflect the completed work as a result of the building permit. The Municipal Property Assessment Corporation (MPAC) will mail you a supplementary or omitted assessment notice that outlines such assessment values and the effective date(s) they take effect.
Supplementary/omitted property tax bill
For taxation purposes, you will receive a tax bill at a later date called a "supplementary" tax bill. The bill will reflect the additional change in your assessment and taxes owing will be adjusted accordingly. Supplementary taxes are determined by multiplying the supplementary assessment by the applicable tax rate and prorating this amount based on the number of days the building has been completed or occupied for the year.
If the supplementary/omitted tax bill is for a new home, the owner will be responsible from the effective date of occupancy and/or possession; therefore, creating multiple year supplementary/omitted tax bills. If the supplementary notice is for additions or improvements to your property, your property taxes will increase. It is important to note that your land may have been previously assessed and taxed accordingly, and your supplementary/omitted tax bill may only be for the structure portion of the property. If your supplementary notice is only for a change in classification, the municipality applies a new tax rate to your property. The new tax rate could be higher or lower than what was previously billed.
The bill must be paid by the due date indicated on your supplementary tax bill. Municipalities must provide 21 days’ notice from the date issued to the due date under provincial legislation. Additional assessment occurring from building a new home or addition can result in a supplementary tax bill that can amount to thousands of dollars. It is a good idea to plan for this billing as soon as you start work on your property by putting money aside monthly to pay the bill when it comes due.
For a rough estimate of what you could expect to see on your tax bill and/or supplementary/omitted tax bill, use our property tax estimator.
Note: If you are enrolled in the City’s Pre-Authorized Tax Payment Plan, any supplementary tax bill issued must be paid separately by the due date indicated on your tax bill.
Examples of supplementary/omitted assessments
The year in which you build, your land and house are assessed and taxed separately. Once the house is assessed and billed, the following year the taxes are combined and billed in the normal billing cycle. For ease of understanding this sample, the 2020 supplementary bill is for the period of January 1, 2020 to December 31, 2020, no phased in values were utilized for the 2021 tax year, nor have any Solid Waste, Local or other charges factored in.
|Billing Type||Year||Description||Assessment Value||Billing Amount||Billing Date|
|Interim||2020||Land only||$ 100,000||$538||March 2020|
|Final||2020||Land only||$ 100,000||$547||June 2020|
|Supplementary||2020||Supplementary Assessment (Building only)||$ 338,000||$3,669||July 2020 through November 2020|
|Interim||2021||Land and Building||$ 438,000||$2,377||March 2021|
|Final||2021||Land and Building||$ 438,000||$2,512||June 2021|
Appealing your property assessment
If you believe your assessment is incorrect, you must contact MPAC to review your property’s assessed value by applying for a Request for Reconsideration (RfR). This is the mandatory first step in the appeal process for residential, farm and managed forest properties. For other property classes, filing an RfR is optional. Owners of such properties may instead file an appeal directly to the Assessment Review Board (ARB) if they so choose (see below). The deadline for submitting your RfR is printed on your property assessment notice and is typically March 31 of the taxation year for which you wish to appeal. There is no cost to file an RfR application.
If the reconsideration process results in a change to your assessment, it will be amended accordingly. If not, or if you are not satisfied with the amended assessment provided, you can choose to file a complaint with the Assessment Review Board (ARB), an independent tribunal. The deadline for filing an appeal with the Board is 90 days after MPAC has notified you of its decision in relation to your RfR submission. There is a cost associated with an ARB appeal. Both the property owner and MPAC will be asked to appear at a hearing before the ARB to present evidence. The Board's decision is binding for both the owner and MPAC. If the Board reduces your assessed value, your taxes will be subsequently be adjusted by the City of Ottawa. The City also has the right to appear at your hearing before the Board. The Assessment Review Board Notice of Complaint form and a list of associated costs for filing an ARB appeal are available on the ARB’s website.
Online property tax and assessment tools
- Property tax estimator
An online tool by the City of Ottawa that provides property owners with an estimate of what their total annual property taxes could by using the property's assessment value and the services received.
An online tool owned by MPAC that allows residents to view how their property was assessed, compare their properties to others in their neighbourhood, review the information MPAC has on file for their property, and more.
Real estate prices and your property taxes
Rise in housing market costs
A significant increase in property value does not automatically translate to a property tax increase. Municipalities cannot benefit from market value increases. The City of Ottawa adjusts the baseline tax rates downward to account for overall assessment increases and collect the same revenues. Visit our tax policy webpage for further information.
Purchase price vs. assessment value
The listing or purchase price of real property is not necessarily the same as its assessment value. The sale of real property is affected by many factors, such as a buyer's desire to acquire a particular property and a seller's willingness to reduce the sale price in order to achieve a sale. This could result in similar properties selling for different amounts, which would result in different amounts billed. MPAC therefore determines an assessed value that is in the middle range of selling prices for similar properties. This ensures that the tax burden is equitably shared among similar properties.
Another reason the assessed value and price might not be the same is that the market may have changed between the current valuation date of January 1, 2016 and the date you purchased or negotiated your property.
Determining ownership of a property
Names and mailing information for property owners are available in the City's Roll Books, prepared by the Municipal Property Assessment Corporation (MPAC).
The Roll Books are available for viewing at the City Hall Client Service Centre.
We strongly recommend you schedule an appointment with us but walk-ins will be accepted between 9 am - 4 pm. Priority will be given to scheduled appointments.
Please select a location to book an appointment time:
If you have questions about your Property Assessment Notice (PAN), assessed value or about assessment in general, please contact MPAC at 1-866-296-6722 (TTY 1-877-889-6722) or through their online form.
If you have any questions about your municipal property taxes or municipal tax rates, please contact the City of Ottawa Revenue Services at 613-580-2444 (TTY 613-580-2401) or by e-mail at firstname.lastname@example.org.