Latent defects · Gatineau · Civil Code and local risks
What a latent defect is, what the Civil Code says, Gatineau-specific risks (floods, clay, radon, oil tanks) and what buyers and sellers should do.
In Québec, the seller of a house owes the warranty of quality: the property must be free of latent defects (article 1726 of the Civil Code). A latent defect is a hidden defect, unknown to the buyer, that existed at the time of the sale and is serious. In Gatineau, three local risks keep coming up: the flood zones of the Ottawa and Gatineau rivers (2017 and 2019 floods), areas exposed to landslides on clay soils, and radon, at 200 Bq/m³ or more in 17.0% of homes in the Ottawa-Gatineau region according to the 2024 pan-Canadian survey. A buyer who discovers a defect must notify the seller in writing within a reasonable time (article 1739). Sources: Civil Code of Québec, City of Gatineau, 2024 pan-Canadian radon survey.
In Québec, the seller of a house owes the warranty of quality: the property must be free of latent defects (article 1726 of the Civil Code). A latent defect is a hidden defect, unknown to the buyer, that existed at the time of the sale and is serious. In Gatineau, three local risks keep coming up: the flood zones of the Ottawa and Gatineau rivers (2017 and 2019 floods), areas exposed to landslides on clay soils, and radon, at 200 Bq/m³ or more in 17.0% of homes in the Ottawa-Gatineau region according to the 2024 pan-Canadian survey. A buyer who discovers a defect must notify the seller in writing within a reasonable time (article 1739).
According to Éducaloi, four conditions must be met: the defect is hidden (a prudent and diligent buyer could not see it without an expert), it was unknown to the buyer, it existed at the time of the sale and it is serious (the buyer would not have bought, or not at that price, had they known). A crack visible during the visit, an obvious damp smell or a defect flagged by the inspector are not hidden.
| Article | What it provides |
|---|---|
| 1726 | The seller warrants that the property is free of latent defects; a defect is apparent if a prudent and diligent buyer can notice it without needing an expert. |
| 1728 | A seller who knew of the defect, or could not have been unaware of it, must also compensate the buyer's damages. |
| 1729 | The defect is presumed known when the seller is a professional (a builder, for example). |
| 1732 and 1733 | The warranty can be excluded by contract, but a seller cannot escape it for a defect they knew and hid, unless the buyer buys at their own risk from a non-professional seller. |
| 1739 | The buyer must notify the seller of the defect in writing within a reasonable time after discovering it. |
| 2925 | The action is prescribed after three years. |
Official text: Civil Code of Québec on LégisQuébec (French version).
After the 2017 and 2019 floods, a special intervention zone covered the 0-20 year flood zones and every area flooded in 2017 or 2019, banning new construction and backfill; it was drawn from aerial photos taken on April 29, 2019 (City of Gatineau). Since March 1, 2026, a new provincial regulatory framework governs flood zones, shoreline mobility and the littoral (Government of Québec). A flooded and repaired house is not necessarily a latent defect if it was disclosed; a hidden past water infiltration can be. Check the map before making an offer: our page on flood zones in Gatineau explains how.
Gatineau maps landslide-exposed areas (zones NA1, NA2, RA1 summit and RA1-NA2), described as predominantly clay soils; the map can be viewed in the City's urban planning Geoportal, and a geotechnical assessment is required for some permits (City of Gatineau). For a buyer, the question is twofold: is the house in a zone, and was work (extension, pool, backfill) done without the required assessment?
Radon is a natural, odourless radioactive gas that seeps in from the ground. In the Ottawa-Gatineau region, the 2024 pan-Canadian radon survey measures an average of 85.9 Bq/m³ and 17.0% of homes at 200 Bq/m³ or more, against 16.7% for Québec as a whole (2024 pan-Canadian survey). Health Canada recommends acting above 200 Bq/m³ and testing for at least three months, ideally in fall or winter (Health Canada). Radon can be fixed (sub-slab depressurization); a test before or after the purchase avoids the surprise.
The OACIQ Declarations by the Seller form asks specific questions about a current or removed fuel oil tank and contaminated soil, as well as flood zones, landslides and pyrite, pyrrhotite and radon tests (OACIQ DV form, in French). In older neighbourhoods, a forgotten buried tank is a classic risk: ask for proof of removal.
An estate, a foreclosure or a seller who never lived in the house often sells without legal warranty, at the buyer's own risk. The buyer then loses the latent-defect remedy, unless the seller knew of the defect and hid it (Éducaloi). The price should reflect it, and a pre-purchase inspection becomes essential.
A seller who knew of a defect and kept quiet must also pay damages (article 1728). Filling in the Declarations by the Seller carefully, attaching work invoices, an up-to-date certificate of location (certificate of location in Gatineau) and the tests done (radon, pyrite if relevant) protects the seller as much as the buyer. A broker on our team walks you through the form.
The action is prescribed after three years (article 2925 of the Civil Code), but the written notice to the seller must be given within a reasonable time after the discovery (article 1739).
It depends on the facts: seriousness, the seller's knowledge, whether it could be detected. A test done and disclosed settles the question. With 17.0% of Ottawa-Gatineau homes at 200 Bq/m³ or more, it is worth measuring.
The zone itself is public (City map): it is not hidden. A past infiltration kept quiet can be. Read the flood zone section of the Declarations by the Seller.
See the Gatineau real estate guide: prices in the five sectors, the ring and all our pages.
This page summarizes the law in force on October 24, 2026 and does not replace advice from a lawyer or a notary. Sources: Civil Code of Québec (LégisQuébec), Éducaloi, OACIQ, City of Gatineau, Government of Québec, 2024 pan-Canadian radon survey, Health Canada.
Also available in French: version française de ce guide.
Published September 7, 2026 by the Loaa & Manseur team, the number 1 team at RE/MAX Platine in 2024 and 2025, 6th RE/MAX team in Quebec, 15th in Canada and in the global top 50 according to the official RE/MAX ranking. Tell us about your project.
Équipe no 1 de RE/MAX Platine en 2024 et en 2025, 6e au Québec, 15e au Canada et dans le top 50 mondial au classement officiel RE/MAX. Réponse en moins de 24 heures, sept jours sur sept.