In Ontario, seller's disclosures depend on the nature of the potential defects a home may have.
The law differentiates between two types of defects - patent defects and latent defects.
Patent defects are visible to the buyer or to a home inspector. They are usually easy to see, which is why it's not the seller's responsibility to disclose to potential buyers. Examples of patent defects are visible cracks in a foundation wall, missing safety railings, stains from leaks that suggest either a plumbing or a room leak, etc.
It is the buyers' responsibility to look carefully, research, ask the right questions, and have the home inspected if they'd like.
Latent defects are not obvious and can be difficult to detect, even by a home inspector. Examples of latent defects are major structural issues, basement flooding during heavy rainfalls, hidden fire damage, or mould.
If a seller is aware of such defects and chooses to not disclose it, they could be liable and can be potentially sued by the buyer.
One way to determine any latent defects is to have your Real Estate Agent ask the seller's representative specific questions about any potential latent defects.
It's ALWAYS a good idea to get your own home inspection done, as the information you receive might affect your decision to buy, offer less, or include specific clauses and conditions in your offer to purchase.
It's important to remember, each home is different and may present a variety of issues. Working with a knowledgable agent as well as other professionals such as lawyers, contractors, and home inspectors will help cover your bases and determine such issues before making any major decisions.