Do you have to disclose a former grow op in Ontario?

No Ontario law makes a seller declare a former grow op, but a Toronto home the police reported cannot be lived in until it is fixed. Fines reach $100,000.

Ontario has no statute that names cannabis grow operations and orders a seller to declare one. That is the short answer, and it is also why the question keeps coming back. What does exist is a set of duties sitting on the agents in the deal, a Toronto bylaw that decides whether anyone may legally live in the house, and a City report any buyer can order for $214.79.

Is a seller required by law to disclose a former grow operation?

No Ontario law names grow operations and requires a seller to declare one. Whether a particular seller owes a legal obligation to disclose a particular fact is decided case by case, and it is a question for a real estate lawyer rather than for a listing agent.

Ontario's real estate rules treat that obligation as something that already exists rather than creating it. Section 22.2 of Ontario Regulation 567/05, made under the Trust in Real Estate Services Act, 2002, reads: "If a seller has a legal obligation to disclose a fact to the buyer and the fact is known to the broker or salesperson who represents the seller, the broker or salesperson shall disclose the fact to every buyer who expresses an interest in the real estate."

Read that closely. The trigger is the seller's own obligation, which the regulation does not itself define. Once that obligation exists and the seller's agent knows the fact, the agent has no discretion left. Every interested buyer gets told, and under the same section the agent has to make best efforts to obtain a written acknowledgement back from each of them.

The Code of Ethics, Ontario Regulation 365/22, adds the floor underneath all of it. Section 5 requires a registrant to make best efforts to ensure that any representations are accurate and not misleading. Saying nothing and saying something false are treated very differently in Ontario, which is exactly why a written question is worth more to a buyer than a spoken one.

What does your own agent have to do?

Find out. Section 22.1 of Regulation 567/05 requires a broker or salesperson representing a client to take reasonable steps to determine the material facts relating to the purchase or sale, to disclose those facts to the client as soon as possible, and to advise the client to consider whether they affect the decision to buy or sell.

A material fact is defined in section 1(1) of the same regulation as "a fact that would affect a reasonable person's decision to acquire or dispose of the interest". A property that police have reported to the City as a former grow operation clears that bar without much argument. It changes what the home is worth, what it costs to insure, and in Toronto whether it may lawfully be occupied at all.

There is a third duty worth knowing. Section 22.3 says that if the seller has completed a written statement about the property for buyers, the seller's agent must tell every interested buyer that the statement exists and make it available on request. These statements are voluntary in Ontario and nobody has to fill one in. But once one exists, its existence cannot be kept quiet.

What does Toronto require before anyone can live in the house?

Remediation, and the standard sits in Chapter 565 of the Toronto Municipal Code, adopted by council on 27 September 2007.

The bylaw's definition is narrow and mechanical. A marijuana grow operation is any property that the Toronto Police Service, the Ontario Provincial Police or the RCMP "has identified in writing to the City as having contained a marijuana grow operation". A rumour from a neighbour does not engage the bylaw. A written police report to the City does.

Once it applies, section 565-2D requires the owner to do four things:

• remove all equipment and materials used in the operation
• remove and restore any alteration made to the property as a result of it
• repair any damage it caused, including mould and water damage
• obtain and comply with every inspection, order, permit and approval required for lawful use of the property

Section 565-2E is the one with teeth. No person may allow the property to be used as a dwelling, or for any other purpose that requires people to occupy it, until that work has been done.

If the owner does not do it, the City may enter, do the work itself and bill them. Unpaid after 90 days, those costs become a lien against the property, are added to the tax roll and are collected in the same way as property taxes. Fines under section 565-5 run to $5,000 for a first offence, $25,000 for a second, and $100,000 for a third or subsequent one.

This is the part that matters more than the disclosure question does. A buyer who closes on an unremediated Toronto house inherits the order, the work and the bill.

Are four plants in a basement a grow operation?

No. Under the federal Cannabis Act, adults may grow up to 4 cannabis plants per residence for personal use, from licensed seed or seedlings. Ontario applies the same number and adds conditions: you have to be 19 or older, it has to be for your own use, the starting material has to have come from the Ontario Cannabis Store or an authorized retailer, and it cannot be forbidden by your lease or your condominium's rules.

Four legal plants in a spare room are not what Chapter 565 is aimed at. It is aimed at the converted house: electrical service bypassed around the meter, joists cut through for ducting, humidity held high enough for long enough to grow mould inside the walls. The damage is the point, not the plant.

How do you find out before you firm up?

Ask in writing, then check the record yourself rather than relying on the answer.

• Put the question in writing to the listing brokerage. A written question is much harder to answer carelessly than a spoken one, and it leaves a record of what you were told.
• Ask whether the seller completed a property information statement. Section 22.3 obliges the seller's agent to tell you if one exists and to make it available if you ask.
• Order a Property Information Report from the City of Toronto. It sets out the building permits on file for an address, the status of inspections, and any outstanding orders under the Ontario Building Code, the zoning bylaw and the property standards bylaw. The fee is $214.79 as of 1 January 2026 and the City aims to turn it around in about five business days.
• Keep a home inspection condition and brief the inspector. Tell them what you are looking for. Patched roof vents, fresh drywall in odd places, a newer electrical panel in a house that has had no other work, and the smell of a basement after a warm afternoon are the things worth a second look.

Outside Toronto the disclosure position is the same, because Regulation 567/05 is provincial. What changes is the municipal layer. Every municipality writes its own property standards and remediation rules, so the question to ask in Mississauga, Vaughan or Oshawa is what that city's own bylaw requires and whether an order is open against the address.

None of this makes a former grow house unbuyable. Plenty have been stripped, rewired, inspected and signed off, and the paperwork proving it is the most valuable thing a seller in that position owns. What gets people hurt is buying one where that work was never done and nobody asked. We walk clients through this on both sides of the deal, whether you are buying or selling.

This sets out what the published rules say as at 7 September 2026. It is not legal advice, and a lawyer should look at the facts of your own deal.