If you have a slow drain or if water is running upstairs, it is urgent that you call a plumber who will come with all the tools and fix the problem. There is a good company in Toronto https://drainexpress.ca/main-sewer-line-replacement-service-in-toronto-gta/ where you can find such a person. Once we had a burst pipe and an hour after our call the plumber arrived at our home, the impression after cooperation we had only the best, so I recommend to contact this company!