Quebec Municipal Assessment After Renovations: How the Roll Gets Amended Mid-Term

You added an extension, built a garage or finished the basement, with a proper permit. Months later, sometimes more than a year later, the municipality writes: the value on the assessment roll has changed, and a corrected tax bill is on its way. If you sell in the meantime, that catch-up can land after the deed is signed at the notary's office. In other provinces this is often called a supplementary assessment; in Quebec, the assessor amends the roll in force by certificate. This article covers how that works, how far back it can reach, how to contest it, and how a seller handles it in the sale. How the tax bill itself is built is explained in our article on the property tax bill in Quebec.

A three-year roll that is kept up to date

A Quebec property assessment roll stays in force for three consecutive municipal fiscal years. The values on it are not recalculated every year. They are, however, corrected when the property itself changes.

Quebec's Act respecting municipal taxation has a chapter on keeping the roll up to date, starting at section 174. According to the Ministère des Affaires municipales, the assessor must amend the roll in specific situations, including the construction or demolition of a building. An extension, a new garage or a finished basement changes the state of the property: that is the kind of event the update targets.

The change is made through a certificate issued by the assessor. It affects only your assessment unit. The rest of the street keeps its values until the next roll.

The building permit is what tips off the assessor

You do not have to report your renovations to the assessment department. The permit issued by the municipality does that for you. Quebec City, for example, states that the issuance of a building permit may lead to an inspection of the property by its assessment service.

Not every project changes the roll in force. Quebec City explains that minor changes have no effect on the current roll and no supplementary tax bill is issued; what was observed is factored into the next roll. For a significant change, the assessor sets the value to add to the current roll, and a notice of amendment is sent to the owner.

An effective date that can go back to the work

The notice of amendment states the new value and the date it takes effect. That is not necessarily the date of the notice. It generally matches the event that changed the property, which is why a corrected bill can cover a period that has already passed.

Retroactivity has a limit. The Ministère des Affaires municipales specifies that the effective date of such an amendment cannot be earlier than January 1 of the previous fiscal year. In its own example, for an event on April 26, 2019, the assessor had until December 31, 2020 to amend the roll, and could set the effective date at April 26, 2019.

In practice, then, a corrected tax bill can arrive more than a year after the work is finished, and claim taxes on the added value from the effective date onward.

Contesting the new value: the clock starts with the notice

An amendment made by certificate can be challenged through a request for review. According to the Quebec government, the deadline is the later of two dates: before May 1 following the roll's coming into force, or within 60 days after the notice of amendment is sent. For an amendment made partway through a roll, the 60-day window is usually the one that applies.

The review covers the added value, not the amount of tax. A higher bill on its own is not a ground for review.

The seller's exposure: a bill that arrives after closing

At the notary's office, the year's municipal and school taxes are split between seller and buyer according to the date of sale. That adjustment uses the bills issued at that point. An increase in value that has not been billed yet is not part of it.

If the notice of amendment arrives after the deed, the corrected bill covers a period that partly predates the sale. The buyer, now the owner, receives a bill that includes months when the seller lived in the house. Without a written agreement, sharing that cost turns into an after-the-fact discussion between two parties who no longer have an open contract to settle it simply.

Handling it in the promise to purchase and at the notary's

A seller who completed significant work during the current roll can head off the problem before signing:

• Disclose the work and the permits: what was done, when it was finished, and whether a notice of amendment has already arrived.
• Compare the roll with the actual house: if the roll still describes the pre-renovation house, an amendment remains likely.
• Add an allocation clause to the promise to purchase (Quebec's standard offer form): any supplementary tax for the period before the deed stays with the seller, and the rest with the buyer.
• Discuss a holdback: the parties can agree that an amount stays in the notary's trust account until the corrected bill is received.

One written line before the deed costs little. It keeps a bill received six months later from becoming a dispute between two people who thought the deal was done.