If the tenants are already moving out your options are limited to rectify this situation. You could try writing them a letter stating your concerns about the possibility of damage and about the safety of other occupants of the house as well as the increased consumption of hydro, but that would be all you could do for the time being. Once they have moved out and you discover any damages, as of September 1, 2021, section 88.1 of the Residential Tenancies Act allows a landlord to file a claim for damages with the LTB within one year from the date the tenant is no longer in possession of the rental unit.  The tenant must have moved out of the rental unit on or after September 1, 2021.  However, you will need to know the tenant’s new address or place of work so you can send them a copy of the documents.