Hello, we are building a new bathroom and have left the toilet pipe and the shower pipe open. We have noticed that water from the front bathroom is now draining and coming out of the open toilet pipe (no toilet installed yet). My question is, is this normal or do I have a blockage in another part of the draining system? Is the open pipe act as a vent of sorts and the waste water is actually flowing to the back of the house and up the toilet open toilet pipe?

Also - during construction, the pipes we are talking about (toilet drain, bathroom drain, dishwasher drain were all replaced (not sewer line) in the back of the house and at all times they were dry. We continued using the front bathroom and never had any water flowing to the back of the house. No wall of a sudden, we do have waste water coming from the front bath to the rear bath and out the toilet pipe.


If I cap the toilet pipe, will this remedy the issue until we are ready to install the toilet, or is there probably a blockage someplace else in the old plumbing in the front of the house?


Thank you.

 

You can snake the main drain from one of the cleanouts just in case there is a blockage but most plumbers would look for a clogged vent.