Think Your Ontario Property Assessment Is Too High? How to Challenge MPAC with an RfR and ARB Appeal

Step 1: Decide whether your assessment is genuinely too high. Don’t go on gut feel. Ask one specific question: could my property have sold for this assessed value as of January 1, 2016, in the market at that time? Note that the test is the 2016 market, not today’s. Then log into MPAC’s AboutMyProperty portal to review your property details for free and compare your value against similar homes nearby. If your assessment is clearly higher than comparable neighbours, you have grounds to file.

Step 2: Gather evidence that holds up. What MPAC weighs most heavily is sale prices of comparable properties and the assessed values of comparable properties. Useful material includes: sales of similar homes (same area, type, age, size) around the 2016 valuation date; assessed values of comparable neighbours; a recent professional appraisal; photos documenting a worse-than-recorded condition (foundation, water damage, roof and other structural issues); repair estimates; and zoning information. In short: let the data speak, and the closer your comparables are to your home, the stronger your case.

Step 3: File the RfR (Request for Reconsideration) — for free. This is an internal review request to MPAC and it is free of charge. You can file online or by mail. The deadline is usually March 31 of the tax year, and the exact date is printed on your Property Assessment Notice — always go by the date on your notice. You’ll receive confirmation of receipt. For residential, farm, and managed forest properties, the RfR is a mandatory first step — you cannot go straight to the ARB without it.

Step 4: Wait for MPAC’s decision. MPAC generally responds within 180 days of receiving your RfR; complex cases can be extended, up to roughly 240 days total. The outcome may be: the value is upheld, the value is lowered, or — in some cases — it can be raised. During the review, an MPAC representative may contact you to discuss the property and the evidence you submitted, so keep your comparables and photos organized and ready to explain. If you accept the result, you’re done. If not, move to the next step.

Step 5: Still disagree? Appeal to the ARB (Assessment Review Board). The ARB is an independent tribunal under Ontario’s Ministry of the Attorney General — separate from MPAC. You must file your appeal within 90 days of MPAC’s RfR decision. ARB fees are charged per roll number: $132.50 per roll number for residential, farm, and managed forest properties (less a $10 discount for filing online), and $318.00 per roll number for commercial, industrial, multi-residential and other property types (also less $10 for online filing) (source: Tribunals Ontario, 2026).

My practical advice (Arthur Zhao): run the value check first. Before you file, estimate this: if your assessment really came down, how much would you save in a year at your municipality’s tax rate? Put that number against the time you’ll spend, the possible ARB fee, and any cost of a professional appraisal or representative. For many slightly over-assessed homes, the savings can be modest, and the effort may not pay off; for clearly anomalous assessments or higher-carrying-cost properties, an appeal is well worth it. The strongest cases I’ve seen are properties whose assessed value sits noticeably above near-identical homes on the same street — that gap is exactly what an RfR is built to correct. I can pull the 2016-era comparable sales for your area to test whether you actually have an over-assessment case before you commit, so you’re not filing on a hunch.