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Buyer Toolkit & Reference · Jul 8, 2026 · 6 min read
📖 Buying

Latent vs Patent Defects: What Ontario Sellers Must Disclose and What "Buyer Beware" Really Means

"Buyer beware" is real, but it has limits. Understand latent vs patent and you’ll know which problems you’re expected to find yourself, and which a seller becomes liable for by hiding.

Arthur Zhao · Broker · AZ Real Estate Partners · 2026-07-08
Quick Answer

In Ontario, does a seller have to tell me about every problem with the house?

No. Ontario’s default is caveat emptor (“buyer beware”): for a patent defect (visible on a reasonable inspection), the seller generally has no duty to disclose and the risk sits with the buyer. A seller must disclose a latent defect (not discoverable on a normal inspection) only in limited cases — where the seller knew of it and it makes the home dangerous or unfit to live in. And a seller can never actively conceal a defect or lie. Sources: McGrath v. MacLean (1979) and Cotton v. Monahan (2011 ONCA).

Sources: RECO (reco.on.ca, 2025); Ontario cases McGrath v. MacLean (1979), Cotton v. Monahan (2011 ONCA), Vieira v. Dawson (2018 ONSC 413)

I’m Arthur Zhao. Buyers often ask me, “doesn’t the seller have to tell me about the problems?” — and that’s a dangerous assumption. In Ontario the seller’s disclosure duty is actually narrow; most of the risk falls on the buyer’s due diligence. But the line isn’t unlimited: a seller who knew of a hidden defect that makes the home dangerous or unfit, and stayed silent, can be liable — and concealment or fraud blows through “buyer beware” entirely. Here’s where the line sits. (This isn’t legal advice — for a specific deal, consult a real estate lawyer.)

Patent (visible) vs latent (hidden)

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Default: caveat emptor / buyer beware

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Exception: known + dangerous/unfit latent defect

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Red line: concealment / fraud

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Buyer’s moat: get an inspection
1

Patent defect: the one you’re expected to find

A patent defect is “a defect which is readily apparent to someone exercising reasonable care in their inspection of a property” (Vieira v. Dawson, 2018 ONSC 413) — visible cracks, a stained ceiling, obvious water damage, a sagging roofline. For these, the seller generally has no duty to disclose, and the risk is the buyer’s: you’re expected to inspect and investigate. Source: Ontario case law (2018).
2

Latent defect: hidden, not discoverable

A latent defect is present but not obvious and not findable by an industry-standard inspection — a leaking foundation behind finished basement drywall, hidden mould, a basement that floods only in heavy rain. This is where a disclosure duty can be triggered.
3

The narrow door where a seller must disclose

The leading test, McGrath v. MacLean (1979, Ontario Court of Appeal): a seller may be liable where they knew of a latent defect that renders the premises unfit for habitation or dangerous in itself and did not disclose it. The pivot is the seller’s actual knowledge (or wilful blindness) — the mere existence of the defect isn’t enough. Source: McGrath v. MacLean (1979).

💡 Fraud, active concealment, or misrepresentation defeats caveat emptor — even for defects that would otherwise be “buyer beware.” A seller who paints over a crack, hides water damage behind new drywall, misleads, or is wilfully blind is not protected. “Concealment” requires “an intention to hide from view some defect of which the vendor is either aware or wilfully blind” (Cotton v. Monahan, 2011 ONCA), and silence about a known major latent defect can itself be an intention to deceive (Jung v. Ip, 1988).

The SPIS and the agent’s separate duty

The SPIS (Seller Property Information Statement) is voluntary — an OREA form on which a seller answers questions about the property; it’s not mandatory. If a seller completes one and gives it to their agent, the agent must disclose its existence to every interested buyer and provide a copy on request (RECO). But many Ontario lawyers advise sellers against signing one, because it invites disclosure well beyond the narrow legal duty and expands liability for any inaccuracy. Keep two things separate: the agent’s / brokerage’s duty to disclose material facts under TRESA is a broader, separate duty that binds the registrant — not the seller directly. Sources: RECO / Cheadles LLP (2025).

⚠️Waiving the home inspection to win a GTA bidding war removes the buyer’s main protection. An inspection is the tool that turns potential hidden problems into discoverable patent ones and satisfies your due-diligence burden — but it does not shift the risk of a genuinely latent defect the seller knew of and concealed; that stays the seller’s liability. Don’t throw the protection away to win the bid.

Frequently Asked Questions

Q

Does a seller in Ontario have to disclose problems with the house?

A

Only narrowly. Under caveat emptor, a seller generally need not disclose patent (visible) defects. A seller must disclose a latent (hidden) defect if they knew about it and it makes the home dangerous or unfit to live in — and can never actively conceal or lie. Sources: McGrath v. MacLean (1979); Cotton v. Monahan (2011 ONCA).

Q

What’s the difference between a patent and a latent defect?

A

A patent defect is one a buyer could spot on a reasonable inspection (visible cracks, water stains); a latent defect is hidden and not discoverable on a normal inspection (a leak behind finished walls). The distinction decides who bears the risk. Source: Vieira v. Dawson (2018 ONSC 413).

Q

Is the SPIS mandatory in Ontario?

A

No. The SPIS is a voluntary OREA form; a seller isn’t required to complete one. But if a seller does, their agent must tell every interested buyer it exists and provide a copy on request. Source: RECO (2025).

Q

Should a seller sign an SPIS?

A

It’s a judgment call worth legal advice first. Many Ontario lawyers advise against it because it asks the seller to disclose far more than the law requires, increasing liability for any inaccurate answer; its answers are stated to be for information only, not warranties. Sources: Cheadles LLP / Larson Lawyers (2024–2025).

Q

Does a home inspection protect the buyer?

A

It’s the buyer’s main protection and satisfies the due diligence expected under caveat emptor — turning many potential hidden issues into discoverable ones. But it doesn’t shift the risk of a truly latent defect the seller knew of and concealed; that stays the seller’s liability. Waiving it removes the protection. Sources: RECO guidance and the cases above.

Related Reading

The Complete Ontario Home Inspection Guide →


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