Hi, I had the same problem as you, except with an apartment.
They said I had to, and they made me get rid of my dog I had at the time. I was very angry later on when I found out that there was no reason at all for them to have made me get rid of him. There were not allowed to do so. I called the ORHT and they told me that the only way that they could make me get rid of him was if: he was barking a lot, I wasn't cleaning up after him, he was vicious or a potential threat to others, or if he was ruining the enjoyment of someone else's life. None of those EVER occurred with me and my dog. I NEVER received any complaints from anyone about him. The dumbest thing is, where I live, you're not allowed to actually own a dog, but you can "take care of one". It makes no sense to me!
My best suggestion to you is to call the Ontario Rental Housing Tribunal at: 1-888-332-3234.
They'll give you the information you need to know.