A strange thing has been happening for a while, hasn't gone away on its
own, and it's time to investigate. This started happening last winter.
My upstairs bathroom has a toilet, sink, and shower. When I flush the
toilet, the shower drain gurgles. No toilet water backs up into the
shower, and in fact as near as I can tell, the gurgling seems to be the
result of a _suction_
on drain pipe, rather than a backup.
The house has been prone to roots blocking the outgoing sewer drain in
the past, but no problems with this recently. There's no reason to
suspect any sewer line blockage at this time.
My thought was maybe there is a blockage in the vent stack somewhere. In
this scenario, when the toilet flushes, the rushing water causes a
sympathetic suction on the associated drain pipes, including the shower
drain. No gurgles in the sink drain, but it's farther away and maybe on
a different vent.
I guess I could call a plumber to investigate, but that gets expensive
and the noise is only mildly irritating. Anything I can check on my
Thanks in advance!