Can you sell a house with radon in Quebec?

Can you sell a Quebec house that has radon, or a result above 200 Bq/m³?

Yes. No statute cited on this page forbids the sale because radon is present, or because a test is above 200 Bq/m³. What the sale does not skip is saying what you know. Health Canada’s guideline page says to take corrective action if the average annual radon level exceeds 200 Bq/m³ in the normal occupancy area, to act sooner the higher the level is, and, if you have tested and the level is above the guideline, to take that action within 1 year (Radon guideline). No sentence on that page says a deed waits for the action, or for a result under 200 Bq/m³.

What does the guideline mean, and how does Health Canada say to test?

The same page says the Canadian guideline is 200 becquerels per cubic metre (Bq/m³). Its words on health are these: “While the health risk from radon exposure below the Canadian guideline is small there is no level that is considered risk free.” It is the choice of each homeowner what level they are willing to accept. This page does not add a medical claim to that sentence. A normal occupancy area is any part of the building where a person is likely to spend more than 4 hours per day. The page’s examples include a finished basement with a family room, a guest room, an office or a workshop, and a basement apartment. The guideline excludes a crawl space, an unfinished basement, and an area normally closed off or used infrequently, such as a cold room, a storage area, a furnace room or a laundry room.

The measurement guide says a test of 3 to 12 months is how to estimate the average annual level, with a minimum of 91 days during the heating season. A test can start at any time of year. Fewer than 91 days in the heating season can underestimate the average and may call for a re-test. The guide does not, on the page read here, name October to April as that season. All measurements should be in a normal occupancy area of the lowest lived-in level, a space where someone spends more than 4 hours a day. Within the room, the device goes in the breathing zone, at least 30 cm above the floor. The kitchen, bathroom, laundry room and storage rooms are not suitable. The device should not sit beside a sump, in a crawl space, or next to an exposed foundation crack. Only one detector is required under the guide. Health Canada strongly recommends a device on the C-NRPP list. The guide also says that, under CSA and ANSI standards, repeated results may vary by up to ±25%, so a result slightly below 200 Bq/m³ may in truth sit above it, and a result slightly above may sit below. If the long-term result is above 200 Bq/m³, the guide says to act within 1 year, sooner if the level is higher, including when fewer than 91 days fell in the heating season. If the result is below 200 Bq/m³ and fewer than 91 days fell in the heating season, the guide says to re-test in the next heating season. A result under 91 days is not the reading the guideline uses (Guide for radon measurements in homes).

The Cross-Canada Survey page is not a reading of one house. The 2012 final report says 6.9% of Canadians were living in homes above 200 Bq/m³, on a population-weighted estimate. In Quebec, the raw share of homes tested that were above 200 Bq/m³ was 10.1%, and the population-weighted share was 8.2%. For the Montréal health region the report lists 73 participants and a raw share of 6.9% above 200 Bq/m³, with none of those results above 600 Bq/m³. The same page says those results should not be used to decide the risk in a home or whether to test it, and that the only way to know if a home has an elevated level is to test, regardless of location. A note on that page, about a 2024 survey published with Health Canada staff, says approximately 1 in 5 houses in Canada, 17.8%, were at or above 200 Bq/m³. That note does not give a Quebec or Montréal figure, and it is not the 2012 percentage (Cross-Canada Survey of Radon Concentrations in Homes, final report).

What do Quebec, the INSPQ and Montreal public health say?

Quebec.ca, updated 31 October 2024, says radon is a radioactive gas from uranium in the soil, that it can enter through the foundation, and that it has no colour, odour or taste. The page says to measure with a monitor, in becquerels per cubic metre, placed in the basement about one metre from the floor, or on the first floor if the basement is not occupied. It says not to rely on a test from a neighbouring house or from the neighbourhood. A passive monitor stays in place at least three months, preferably in winter, which that page sets as October to April. Outside that period, a result under the guideline is repeated in winter. The page says the average concentration in Quebec basements is around 37 Bq/m³, and that concentrations can sometimes exceed 1,000 Bq/m³. It says that if the concentration exceeds 200 Bq/m³, corrective measures should be taken within one year. That placement, about one metre up in the basement, is not the same sentence as Health Canada’s lowest lived-in level. This page does not merge them. No sentence on the Quebec page says a deed waits for the measures (Residential radon).

The INSPQ’s note of 25 January 2010 says that, since June 2007, Health Canada lowered the guideline for radon in indoor air from 800 to 200 Bq/m³. This page uses that sentence for the change of number. It does not use the note for a medical claim (Protection de la santé publique contre le cancer du poumon associé au radon, page in French).

On 16 April 2025 the CIUSSS du Centre-Sud-de-l’Île-de-Montréal wrote that, since 15 April 2025, the Direction régionale de santé publique de Montréal gathers, at santepubliquemontreal.ca, the content aimed at the public (Un nouveau site Web pour la Direction régionale de santé publique de Montréal, page in French). A page there that states 200 Bq/m³ was not found. Two current pages name radon, and neither states that number or a condition of a deed. The housing page says a dwelling of quality is, among other things, free of chemical and radiological contaminants, and it names radon, lead and asbestos in that list. Later on the same page, radon is an example of a physical contaminant, beside noise and heat (Logement, page in French). The salubrité page names radon, with lead and asbestos, among chemical contaminants in the indoor environment that can affect whether a building is salubrious (Salubrité des milieux de vie, page in French). This page does not choose between those two labels. It quotes them.

What do you declare, and what does the legal warranty still require?

On the French PDF read for this page, marked DV 00001 and V24, copyright 2012 and 2022, the answers are to your knowledge and in good faith. The English PDF, read for the English wording, shows V17 in the margin. Both wordings of D13.2 name radon. The items below follow the French V24 wording. This page does not call the two files one edition (Déclarations du vendeur sur l’immeuble, form DV, page in French).

D13.2 asks whether, in addition to those already mentioned, tests or expert reports have been done on the immovable. The list in parentheses is pyrite, pyrrhotite, radon, ochre deposit, urea-formaldehyde foam insulation, asbestos, air quality, water quality or flow, the foundation drain, or other. If the answer is yes, the form asks whether you can provide the documents. If you cannot, it asks why, and what problem the report showed, if any. Radon is one name in that list. The question is not, on the form, an instruction to order a new test. D15 is where the detail goes: the clause number, the place, the year, and how the situation was dealt with, if it was. The form says to provide the available documents that support the declarations. D14.5 asks whether, in addition to what is already mentioned, anything else could affect the value, the income, the expenses or the use. The form asks that question. This page does not answer it with a number.

The OACIQ’s radon page for licence holders says the broker must ask whether radon tests, or work to correct a radon problem, have been done in the past, and must disclose that information to any prospective buyer. The same page points to clauses D12.1, D12.2 and D13.9 of the declarations form. On the V24 PDF read here, radon is named at D13.2, not under those three numbers. This page follows the PDF for what the form asks. The page is written for a licence holder. On a sale with no broker, you still say what you know, in writing. When the form is the path, and when it is not, is the declaration page already cited (Radon, OACIQ).

Article 1726 says the seller warrants that, at the time of the sale, the property and its accessories are free of latent defects which render it unfit for the use for which it was intended, or which so diminish its usefulness that the buyer would not have bought it or paid so high a price if he had been aware of them. The seller is not bound to warrant a latent defect known to the buyer, or an apparent defect. An apparent defect is one a prudent and diligent buyer can perceive without an expert (Civil Code of Québec, article 1726). Article 1727 is a different event. If the property perishes because of a latent defect that existed at the sale, the loss falls on the seller, who must restore the price. If the loss results from superior force, or from the buyer’s fault, the buyer deducts the value of the property in the state it was in when the loss occurred. This page does not decide when a radon result is that loss (Civil Code of Québec, article 1727). Article 1728 says that if the seller was aware of the latent defect, or could not have been unaware of it, the seller is bound not only to restore the price, but also to make reparation for the injury the buyer suffered (Civil Code of Québec, article 1728). This page does not decide that a given reading is a latent defect.

Article 1729 is a presumption. In a sale by a professional seller, a defect is presumed to have existed at the time of the sale when the property malfunctions or deteriorates prematurely compared with identical property, or property of the same kind. The presumption is rebutted if the defect is due to the buyer’s misuse. The article names a professional seller. It does not name the owner who sells their house (Civil Code of Québec, article 1729). Article 1730 is also a different person. It binds the manufacturer, any person who distributes the property under their name or as their own, and any supplier, in particular an importer, to a seller’s warranty (Civil Code of Québec, article 1730). The article names those persons. It does not name the owner who sells their house. Article 1731 says a sale made under judicial authority gives rise to no warranty of quality. This page is not that sale (Civil Code of Québec, article 1731).

Article 1732 says the parties may add to the warranty, diminish its effects or exclude it, but in no case may the seller exempt himself from liability for his personal acts or omissions (Civil Code of Québec, article 1732). Article 1733 says a seller may not exclude or limit liability unless the defects he was aware of, or could not have been unaware of, and which affect the right of ownership or the quality of the property, were disclosed. The same article makes an exception where a buyer buys at his own risk from a seller who is not a professional seller (Civil Code of Québec, article 1733). The exception is not a permission to stay silent.

Éducaloi says that, if the exclusion is real, the claim for a hidden defect is what is given up, and what remains is to show that the seller deliberately hid something so important that the buyer would not have bought, or would not have paid the same price (Immobilier : acheter sans garantie légale, page in French). The OACIQ says that the waiver will not protect the seller against an action for defects of which he was aware and which he should have disclosed (The legal warranty of ownership and quality). How the clause is written is the as-is page already cited. A notary or a lawyer reads the clause. This page does not.

What papers do you gather?

The report you already have, if you have one, and the documents the form asks you to provide with D13.2 and D15. A letter or a note you already have can go with that file. No page cited here says a new 91-day test is required in order to sign. Health Canada’s guide is about estimating the average annual level in a home. It does not say the deed waits for that test. The deed and the certificate of location are a different list.

What are the ways to sell, including a direct sale as it stands?

Two paths are not the same promise. You can sell with the reading as it is, and say what you know, on the form when that form is used and in writing when it is not. Selling without the legal warranty is a clause in the promise and the deed. It does not cover a result you knew and did not disclose. Health Canada’s one-year recommendation, if the level is above 200 Bq/m³, remains that recommendation. No page cited here says the deed erases it, or that the deed cannot be signed until the action is done.

A direct sale is a further path. Bruce Malcolm buys houses himself on the Island of Montreal and the surrounding areas. He holds no broker, agent, appraiser or inspector licence, and he is not an advisor. There is no inspection and no commission. An offer with no inspection condition does not, by itself, set aside the legal warranty of quality. You say what you know about radon when you send the address: whether a test was done, the result if you have it, where the device sat if you know it, and any system already in place. He does not measure radon and he does not install a reduction system. The closing date is one you choose once the notary can sign. Sending the address starts a conversation (request an offer). The form does not commit you. A notary or a lawyer reads the deed.