If a tenant owes back rent when the property sells, who has the right to collect it, the old or new landlord?

The right to collect rent arrears that accrued before closing generally remains with the person who was the landlord during that period, meaning the seller, unless the purchase agreement or closing documents specifically assign that right to the buyer instead. Simply becoming the new owner does not automatically hand you a claim to rent the tenant owed to someone else before you owned the property.

Going forward, you as the new owner are responsible for, and entitled to collect, any rent that accrues after closing under the continuing tenancy. Because this split can create real confusion if it is not addressed directly, buyers and sellers should specify in writing whether existing arrears are being assigned to the buyer as part of the deal, left with the seller to pursue separately, or otherwise accounted for, such as through an adjustment to the purchase price. Leaving this unaddressed is a common source of dispute once a new landlord starts trying to collect on arrears they did not clearly acquire the right to pursue.