Unless the landlord is aware that their tenant will likely infringe on others’ property rights by virtue of the lease signed, they are unlikely to be liable for the acts/omissions of their tenants.
A recent case confirmed the law in British Columbia. A water leak occurred in a condo building, causing damage to several units. The cause of the leak was never determined, but it was found to have emanated from a particular condo unit. An owner of one damaged condo unit sued the owner of the condo unit the loss emanated from. The claim plead was one of nuisance, being the unlawful interference with another’s property. The unit owner being sued did not occupy the unit in question when the loss occurred, but had rented it out to a tenant.
The British Columbia Supreme Court provided a ruling (Shahgaidi v Zhang, 2018 BCSC 2082 [Zhang]), providing a clear statement of law regarding landlord liability in respect of their tenants, Zhang at para 18:
[18] The starting proposition is that a landlord will not be held liable for the nuisance of a tenant, unless the premises were [leased] for a purpose calculated to cause a nuisance.
The court in Zhang considered the lease of the tenant in questions, and found that while the residential lease included the contemplation of the use of water in the unit (the lease stated “water, a dishwasher, refrigerator and laundry are included in the monthly rent” and a bathroom with a toilet, sink and shower are necessary in any residential unit), the egress of water was not the necessary consequence of providing water for residential uses. The court found that the landlord did not contemplate the existence of the nuisance prior to renting out the unit, nor were they aware of it when it occurred, therefore they were not liable for damage caused by the water egress.