We just finished our bathroom in the basement and we now notice that when we flush the toilet, a little water backs up to the shower. Everything seems to be draining well, the sink and the shower but the problem is when we flush..
All the piping is going down the main sewer line.
????is it venting problem or should we have put in some kind of valve in the pipe so that water would not go towards the shower.
Re: plumbing problem
It could be a vent problem, but more likely, it sounds like you connected the shower drain either to the toilet drain, or too close to it.
It is against code to connect any other drain pipe to the toilet drain, for exactly the reason that a toilet flush will back waste water up into another fixture.
Check to see that the shower drain and the toilet drain both attach to the main drain via separate drain pipes.