Does a Deceased Person's House Go to the Estate if the Co-Owner Has Also Died in Ontario?

It depends on how the owners held title and whether the order of deaths is known. If two people die at the same time or it is uncertain who survived, each person's property is disposed of as if that person had survived the other. Unless a contrary intention appears, joint tenants are treated as tenants in common for this purpose, so each deceased's share goes through that person's own estate rather than passing by survivorship.

Joint tenancy carries a right of survivorship, so where one owner clearly outlived the other the survivor generally takes the whole house. Once an owner's share is in an estate it vests in that estate's trustee, who holds it for the people entitled. Probate is normally required where the deceased owned real property.

If a share is in an estate, Estate Administration Tax counts Ontario real estate at its value at the date of death, less mortgages and other encumbrances. Which estate deals with the house, and who inherits, turns on the wills, the way title was held and the timing of the deaths, so a lawyer can confirm your situation.