Tenant Smoking In Unit

[Jonathan VanderPloeg]

My wife and I have recently taken possession of our first rental property a triplex in Ontario Canada. Less then a week into our ownership small issues are arising already. After meeting with the three inherited tenants we soon realized that one seems to be a "professional tenant" (only has a verbal lease, pays $100 less than market rent, and works for a local property management company; which leads me to believe he knows his rights as a tenant and won't budge on anything unless it directly benefits him) The second tenant appears to be a chronic complainer, and the third tenant seems to be no problem at all. I received a call today from the second tenant notifying me that the "professional tenant" who lives below him, is smoking weed and cigarettes in his unit and the smell is travelling to the upper unit and has been affecting his health and quality of living. Apparently in Ontario, smoking in a unit is not grounds for eviction, even if it was stated in a signed lease agreement. Is there anything I can do to deter the smoking indoors? I will be contacting the offending tenant and requesting that he smoke outside from now on, but I honestly don't see him making an effort to change his habits. Suggestions in this situation are greatly welcomed!