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ktanis
downstairs toilet suck the water from the upstairs toilet when flushed

Hi Everyone,

When I flushed my downstairs toilet, it sucked the water from the upstairs toilet and created a brief "fountain" in the upstairs toilet. Then when I flushed the upstairs toilet, there was a loud "draining" sound from under the upstairs bathtub. Nothing strange occured in the downstairs toilet. *The upstairs toilet is basically right above the downstairs toilet. This is the first time anything like this has happened in the 6 years that we have lived in the house. Recently we had the bathtubs drain pipe replaced.

What's going on here?

Thanks in advance for your tips/advice/wisdom.

dj1
Re: downstairs toilet suck the water from the upstairs toilet when flushed

Check your vent up there on the roof, make sure it's clear of leaves or other things.
How long ago did you have the work on the bathtub pipe done? What did the plumber do exactly?

HoustonRemodeler
Re: downstairs toilet suck the water from the upstairs toilet when flushed

To check the vent pipe use a string and a weight. A flashlight may help but don't drop it down the pipe.

Yeah, what did the plumber do?

MLBSF
Re: downstairs toilet suck the water from the upstairs toilet when flushed

sounds like a venting problem but if it started after the plumber did work to the tub it must be something else. what that "something else" is seems baffeling from your description. the only guess i could make is that he didn't connect something properly or used some incorrect fittings that eventually caused a clog somewhere. i'd get a new "good" plumber in there to see what was done, if it was done correctly and if i wasn't, have him fix the problem or put a scope down the line so he can see what's going on from the inside of the pipe. changing a tub drain should not be able to cause a venting problem for a toilet. let us know what happened, you have piqued my interest.

Mastercarpentry
Re: downstairs toilet suck the water from the upstairs toilet when flushed

Whoever did the plumbing work did it wrong if it always did this after the work was done. You've got venting issues or they tapped into a branch drain instead of a main, and that branch goes to the other toilet. If the symptom occurred later than you've got a blocked vent system.

Either way it's caused by trapped air which cannot find a way to equalize the pressure/vacuum through an atmospheric vent, so it's attempting to vent through another fixture. Hope for a blocked vent. Often just running a garden hose down the vent pipe on the roof will clear a blockage. Do this with no water going into the hose as a filled vent pipe can break loose and create a nice mess as all that water gets pushed out wherever it can fond a way out through other drains!

Phil

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