This is the ratio expressed as a percentage of basic housing costs of homeownership to the gross income of the borrower. Basic homeownership costs including mortgage payments (principal + interest), HELOC payments, property taxes, and heat payments (if there are rental properties these costs must also be included in the calculation). If the property is a condominium, condo (strata/maintenance) fees will also have to be included into the costs. The gross income is typically the before tax income that is reported on line 15000 of your T1-General income tax return and your CRA Notice of Assessment. The formula is GDSR = combined annual home ownership costs / total income X 100%. (Related item is the TDSR, see definition in this glossary)