Property Assessment and Taxation

In Ontario, the Municipal Property Assessment Corporation (MPAC) is responsible for assessing property value according to the Assessment Act and other Ontario government regulations. MPAC is an independent, not-for-profit corporation funded by all Ontario municipalities.

MPAC's property assessments provide the foundation on which municipalities – including the Town of Newmarket – base property taxes. Here is how it works:

  1. Each municipality determines how much it costs to provide all the services in a community – such as waste management, parks, fire protection, roads, sidewalks and public transit.
  2. Once that's done, the municipality takes all of the property values and determines tax rates for different property types to make sure there is enough money to provide these services.
  3. This tax rate is then used to calculate how much property tax residents will pay to their municipality.
  4. In addition to the local municipal tax rate, the Regional Municipality of York sets their tax rates, and the Province of Ontario sets the education tax rate.

Learn more about how property assessment and taxation works by viewing the video below.

On this page

The assessment cycle

​In 2016, MPAC updated the assessed values of more than five million properties based on a valuation date of January 1, 2016. A valuation date is what your property could have reasonably sold for if bought by a willing buyer from a willing seller as of January 1, 2016.

As part of the province of Ontario's four-year assessment cycle, increases in assessed values will be introduced evenly over the 2017 to 2023 property tax years. On August 16, 2023, the Ontario government filed a regulation to amend the Assessment Act, extending the postponement of a province-wide reassessment through the end of the 2021-2024 assessment cycle.

Property assessments for the 2025 property tax year continue to be based on fully phased-in January 1, 2016 current values. Decreases in assessed values will take effect right away.

An increase in the assessment value of your home does not necessarily mean there will be an increase in your property taxes for the current year. Residents with property assessments that have increased more than the average may see an impact.

Visit MPAC's dedicated assessment website to learn more about how your property was assessed, see the information MPAC has on file for your home or to file a Request for Reconsideration. These requests will be reviewed free-of-charge by MPAC. A unique password for each property is printed on the assessment notice. Assessment notices for business properties are expected to be issued during October/November.

Assessment growth

Assessment growth refers to property taxes from new and/or expanded homes and/or businesses to pay for the services they receive. Learn more about assessment growth by watching the video below:

Supplementary/omitted tax billings

Property Assessment Change Notices are issued for additional assessment (such as swimming pools, decks or other additions), new homes or property class changes. The property tax dollars associated with the changes are retroactive to the date of occupancy / purchase, or when the renovation or alterations were completed.

Please note the Municipal Property Assessment Corporation (MPAC) assesses your property for the additional assessment, a new home or a property class change which could take up to three years to occur.

The Town issues your supplementary/omitted tax bill(s) and payments are typically due in two instalments. Depending on the determined assessment, the additional property taxes may be in the thousands of dollars. The Town may be able to assist in preparation for the imminent supplementary/omitted tax bill(s) to minimize the impact of this bill. Please contact the Customer Service Department for additional information and assistance.

Property assessment and taxation frequently asked questions

Contact the Municipal Property Assessment Corporation

Call: 1-866-296-(MPAC) 6722 or 1-877-889-(MPAC) 6722 TTY
Fax: 1-866-297-6703
Web: www.mpac.ca
Write: P.O. Box 9808, Toronto, Ontario M1S 5T9
Visit: 100 Via Renzo Dr. Suite 302, Richmond Hill, Ontario L4S 0B8

Learn more about your property assessment at About my Property