Why is my bathroom sink gurgling
How to Diagnose a Gurgling Sink | Ask This Old House
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[Music]
recently i was out of the house and i
flushed the toilet i would hope so
sorry immediately grab the cameras take
a look they always bring a camera
now listen
oh
the elusive gurgle so that tells me
without looking that that toilet wasn't
vented okay i can only be vented through
the lavatory a thing called a wet fence
so what is it that i'm hearing what is
that gurgle where's it coming when that
slug of water leaves the toilet it's
going there and there's air in the pipe
and it's going to be looking for air
behind that slug of water and it needs a
place to find it the only place i could
actually find it was pulling it the
wrong way down through the drain right
here right next to the toilet now when
something is not vented like this one
was this is what you're going to get
the gurgling that's coming from that
bottle gurgle girl the gurgle that we
heard
now if you do one thing and that's
introduce a vent
so now you've allowed the air to come
okay okay there i'm really yeah you'll
do it full contact
look at the dip see it perfect no
bubbles no girl so take a look what was
underneath
yeah
so this is interesting that's underneath
the sink that's right so this is a full
s trap and it's absolutely illegal and
it doesn't allow for venting of the
toilet
so here it is right here that big pipe
goes by this way it's looking for air
and it's going to pull this way and it's
going to pull down through the trap
normally this is half filled with water
right here the trap
and so this is fully illegal because
it's not vented and it's a full s full s
means water can come here comes up this
short leg and now it can actually by a
siphon can actually pull the trap
empty and that means sewer gas come in
the house and so even though we're
flushing the toilet they're connected
and that's why that's pulling from the
center absolutely the way it's supposed
to be is right here
if you look behind it should come down
from the sink here's the trap and the
water comes this way and then there's a
pipe right here this is called a wet
vent this connects down to the big pipe
where that slug of water goes by from
the toilet and this continues up inside
the house connects to the highest point
up inside the vent system inside the
building s-trap wrong p-trap cropper
that's right um i mean how are you going
to fix it for that guy well to do it
correctly
instead of this hold that up you would
introduce a t like this and then try to
extend this pipe
outside and then up outside the outside
of the building or back into the inside
the building and connect back at the top
a lot of work at this correct at some in
chum jurisdictions they let you do this
which is a thing called a mechanical
vent
and that would sit right here underneath
the flood level of the vanity yeah and
it would allow air to come in this way
to break the vacuum when that slug of
water goes by no gurgle but wouldn't let
sewer gas come out this way ah gotcha
all right so good information great and
we appreciate when you flush it that's
right everybody does
