The Residential Tenancies Act requires landlords to maintain the property and ensure that it complies with health, safety, housing and maintenance standards. It is usually very difficult to prove how bed bugs were introduced to the rental property, therefore it is up to the landlord to take steps to correct the problem. To ensure the effectiveness of your efforts, a landlord will also need the tenant’s help and co-operation. Here is a link to the City of Toronto’s information about bed bugs, http://www.toronto.ca/health/bedbugs/