How we check an address
Every address page is built the same way, from public records, with the same rules for every property. Here is what we use, how we match it, and where the limits are.
Where the records come from
In Montréal, the City’s open data: assessment units and lot outlines, building permits issued since 1990, notices of deterioration, the right of first refusal, housing sanitation inspections, heritage buildings and the inventory of buildings from before 1940, lead service line screening, land use, trees and SPVM crime data. Transit comes from the STM.
For every city on the site: the property assessment rolls of the Ministère des Affaires municipales et de l’Habitation (MAMH), the flood zones and the register of contaminated sites of the environment ministry (MELCCFP), and the address points of the Référentiel québécois des adresses. The date of the data is on every page and on the data sources page.
How records are matched to an address
In Montréal, the assessment units at one address form one building (a plex answers to all its numbers), joined to the roll by its roll number (matricule). Permits are matched by their address and, where it is missing or different, by their location on the lot. Flood zones and contaminated sites are compared with the lot outline.
In the other cities, the page is built from the assessment roll and the address point of the Référentiel québécois; a contaminated site within 20 m of the point counts as on the property. These cities do not have the Ville de Montréal files (permits, notices, right of first refusal, heritage, lead): the pages say so instead of showing “nothing found”.
How findings are written
A fixed set of rules turns the records into findings, each tagged Serious, Check, Note or Clear. For example: a notice of deterioration, the City’s right of first refusal, a protected heritage building, a high-velocity flood zone or a lead line confirmed by the City are Serious; a contaminated site on the lot or a low-velocity flood zone is a Check; a building from before 1970 not tested for lead is a Note.
The free page shows the title of every finding. The full report adds what each record says, what it means for a buyer and what to ask, with the source.
Comparisons such as “older than 80% of the buildings on the street” rank the address against the other addresses on the same street, using the same assessment roll figures.
What a report is not
It is a screening of public records before an offer. It is not a pre-purchase inspection, a certificate of location, a notary’s title examination, an appraisal, legal advice or a broker’s advice.
Some things are not in open data: work done without a permit, the condo syndicate’s documents, servitudes and anything in the land register other than the City’s notices. The report names these gaps and tells you who to ask.
How fresh the records are
We download the data again every week and rebuild every page. Each page shows the date of the data it was built from; a new permit or notice appears after the next update, not the same day.
What we never do
We do not publish owner names or mailing addresses, we do not sell personal information, and no one can pay to add, soften or remove a finding. Every finding names its source so you can check it.
Corrections
If a record on a page looks wrong, write to us through the contact page with the address. We check it against the source and fix our matching if it is ours to fix.