Toilet Drains whenever Shower/Washing Machine is used

[Trisha Thornton]

I have a very old rental house. It's had loads of problems, but the newest one has me looking for help. My tenant recently got a new washing machine. Now whenever she uses the washing machine or shower the toilet drains itself. Has anyone ever had something similar happen or know what the issue could be? I've done some research and my best guess is it's a venting issue. But I think it could also be a main line clog (really hoping that's not the case) or perhaps incorrect plumbing related to the washer.

[Mike Reynolds]

Originally posted by @Trisha Thornton:

I have a very old rental house. It's had loads of problems, but the newest one has me looking for help. My tenant recently got a new washing machine. Now whenever she uses the washing machine or shower the toilet drains itself. Has anyone ever had something similar happen or know what the issue could be? I've done some research and my best guess is it's a venting issue. But I think it could also be a main line clog (really hoping that's not the case) or perhaps incorrect plumbing related to the washer.

I would say check vent first. The issue with a washer is they drain with the use of a pump. That forces water at a high rate through your drain rather than gravity fed. It may be an easy fix though. 

Take a water hose on the roof and try and flush out the vent. It's possible leaves or dirt dabbers have partially blocked the hole. Might even try running a snake down it. If you have enough airflow it should with fine.