The Canada Revenue Agency (CRA) tracks house sales through various means. When a property is sold, the lawyer handling the transaction typically notifies CRA through a tax form called a T2091 or T2091(IND), which outlines details of the sale including the sale price. Additionally, provincial land title offices provide information on property transfers to CRA, enabling them to cross-reference reported sales with their records. CRA also utilizes data from mortgage lenders and real estate agents to ensure compliance. Failure to report a property sale can result in penalties, so it’s crucial to accurately report such transactions to avoid legal consequences.