You generally pay the goods and services tax/harmonized sales tax (GST/HST) when you purchase a new or substantially renovated residential rental property from a builder. If you are the builder of a residential rental property, or if you make an addition to a multiple-unit residential rental property, you are generally considered to have made a self-supply and to have paid and collected tax on the fair market value of the rental property or addition at the time that you lease or occupy the first unit of the property as a place of residence.
As a residential landlord, you cannot claim an input tax credit (ITC) to recover the GST/HST paid or payable on the purchase of a residential complex or that you accounted for on the self-supply of the complex because long-term residential leases are exempt from GST/HST. However, you may be eligible to claim the new residential rental property (NRRP) rebate for some of the GST or the federal part of the HST if you…read on here Which rental properties qualify for the GST/HST new residential rental property rebate?

RC4231 GST/HST New Residential Rental Property Rebate