When reporting the sale of a principal residence in 2018, what should be done if the ADJUSTED COST BASE (presumably the original price paid for the residence) is UNKNOWN?

[symerbee]

The residence was purchased in 1970 and there are no records available for the date of purchase or any other details, including purchase price.

[TurboTaxKim]

When you are unable to determine an exact purchase price or ACB of any Capital Property, you should attempt to acquire as much information on like properties and their "Fair Market Value" at the time your property was purchased.

This can sometimes lead to a bit of detective work on your part which may involve checking if the municipality where the property is located has assessment values available to view in their records or online. Or even inquiring with them about a historical tax value.

If CRA questions you on where you came up with the ACB, you should be able to show them you made every reasonable effort to determine this value.