In a home purchase transaction both the buyer and the seller have responsibilities. The buyer has a responsibility to use "due diligence" to inspect the property in order to discover any "patent" defects. Patent defects are those that are not hidden and may be discovered by a reasonable inspection. There is a rule called "caveat emptor" (or buyer beware) that means that if the buyer does not inspect the property, he cannot later complain of defects which are not inconsistent with the seller's representations about the property. Before the buyer commits himself to buying an older home, it is wise to have it inspected. A home inspector will check the home components, from the basement up to the condition of the roof, that make the home functional and safe.

Even if the buyer decides against having a professional home inspection, and does not carefully inspect the house himself, the seller, or his agent, may not conceal or mislead the buyer about defects that would otherwise be evident. Such action could be fraudulent, thereby permitting the buyer to cancel the contract.

Besides patent defects, which are obvious, there can also be "latent" defects. These would not be revealed by a reasonable inspection. Although there is no implied warranty that a property is of any particular quality, if the seller knows, or could be expected to know that the buyer would not purchase the property if they were aware of the latent defect, the seller has a responsibility to disclose such defects to the buyer.

In general, if the seller did not commit fraud, the buyer can not legally complain if he or she finds a defect in quality, for example a leaking roof, after the sale. Therefore, before the sale, the buyer must investigate the property fully. Most buyers make the purchase subject to inspection of the house by a certified home inspector. In a hot market, with multiple offers on well priced properties, it is common for the buyers to have an inspection done before submitting an offer. In the last few years it has become popular for the listing agent to order a pre-sale home inspection, and have the report available for prospective buyers.

Ontario Real Estate Association form of Agreement of Purchase and Sale provides, in Paragraph 28, that "there is no representation, warrantiy, collateral agreement or condition, which affests this Agreement other than as expressed herein". If the seller makes representations ("promises") about the quality of the property, the buyer should have them written into the agreement. The buyer asks the seller to make written representations about the quality of the property in the property condition disclosure form. The seller responds to a list of questions which becomes part of the contract.

When buying a new house, the buyer similarly needs express written warranties as to the quality of the building and agreement that the builder will repair defects found during the term of the warranty. Most builders provide warranties under the New Home Warranty Program.