Property Assessment & Taxation


Municipal Office

395 Mulock Drive P.O. Box 328 Station Main, Newmarket, Ontario
L3Y 4X7

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The Municipal Property Assessment Corporation (MPAC) is an independent, not-for-profit corporation funded by all Ontario municipalities. MPAC's role is to assess the value of your home according to the Assessment Act and other Ontario government regulations.

​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.

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


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.  Due to the COVID-19 pandemic, the Ontario government has postponed the 2020 Assessment Update. 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 2024 property tax year will 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.

For more information, please visit our FAQ webpage.

Additional information 

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 installments. 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. 

Contact the Municipal Property Assessment Corporation

Call: 1-866-296-(MPAC) 6722
1-877-889-(MPAC) 6722 TTY
Fax: 1-866-297-6703
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.      ​