Quebec Property Assessment: Why Your Neighbour's Increase Isn't the Same as Yours

The new assessment roll is out. Your value jumped; the house next door, which looks like its twin, barely moved. The natural reaction is to suspect a mistake. Sometimes it is one; often it is not. Our article on municipal assessment versus market value in Quebec explains why the roll value differs from what a house sells for. This one answers a different question: how the assessor's method, applied house by house, produces different increases on the same street.

Mass appraisal, not a visit to every house

The assessment roll covers every property in a municipality, all valued as of the same reference date. Visiting each one for every roll is impossible. So assessors use mass appraisal: they analyze market sales, derive reference values from them, and apply those values to each property based on what they know about it.

Two ingredients combine for every house: what the market says about similar homes, and what the file says about this particular one. A gap between two neighbours' increases comes from one or the other, sometimes both.

The neighbourhood unit: your home's reference market

To analyze the market, the assessor divides the territory into neighbourhood units ("unités de voisinage"). A unit groups properties the assessor considers comparable and subject to the same market: the same building type, era, area and use. Sales observed within the unit are used to adjust the values of every property in it.

If sales in one unit rose sharply between two reference dates, all its properties rise together. If the next unit's sales rose less, its properties rise less. The boundary between units can run through the middle of a neighbourhood, along a street, or where the type of construction changes. Two houses facing each other can end up in two different reference markets.

The property file: what the assessor knows about your house

The unit's reference value is then applied to each house according to its features as recorded in its file: lot and building size, year built, number of storeys, quality and condition, finished basement, garage, outbuildings. That file is fed by building permits, inspections carried out by the municipality, and information owners provide.

Two houses that look identical can therefore have different files: one has a finished basement on record and the other does not; one was extended with a permit and the other without; one is recorded with more living area. Conversely, a wrong or missing feature in a file feeds straight into the value, and that is where most genuine errors are found.

Catch-up: a big increase is not always an inflated value

An increase is always measured against the previous assessment, and that assessment was not necessarily right for everyone. If your house was assessed behind the market on the last roll, say because a feature was missing from its file or because its unit was less well calibrated, the new roll brings it back in line. The percentage increase then looks larger than your neighbour's, whose value was already better adjusted.

That is why the size of the increase is a poor signal of error. The useful question is not "did I go up more than next door?" but "is my assessed value consistent with houses that are genuinely similar to mine?".

Type, style and era: what separates two houses on one street

Even within a single unit, not every house responds to the market the same way, and assessors account for that. A detached and a semi-detached house, a bungalow and a two-storey, a 1960s build and a recent one do not share a reference value, even side by side. When the market for one style rises faster than another, the difference shows up in the increases.

To sum up, four causes explain why one street gets different increases:

• two different neighbourhood units on either side of a boundary;
• different features recorded in the files;
• a previous assessment more or less in line with the market;
• a house type or style whose market moved differently.

All four are normal, and none of them signals an error. Only an inaccurate feature in your file, or a gap that none of these explains, is one.

Checking your own assessment: the method

The check comes in two steps. First, look up the roll, available online in most municipalities, for a few houses of the same type, era and size in your area, and compare their values with yours rather than their increases. Then check the features recorded in your own file: area, year, storeys, basement, garage. The municipality or its assessment service can tell an owner what their file contains.

If a feature is wrong, or your value is clearly out of line with comparable houses for no visible reason, the remedy is a request for review, within a deadline that cannot be made up later. Our article on requesting a review of your municipal assessment covers the procedure and the evidence expected.