My basement toilet has started to erupt as a bubble of air blows water
up and out. As far as we can tell it happens on a random basis. We'll
lift the lid and the underside will be all wet. My daughter was
walking through the basement and heard - well, she heard whatever
sound a large under water bubble would make.
Let me describe the drain and vent set-up:
First: This toilet has been installed for as long as I have lived in
the house (25+ years) and has never bubbled before. Nothing has
changed as far as the venting or drains. The toilet flushes fine and
all other fixtures drain normally.
Second: This bathroom is in the corner of the house where all the
drains meet under the slab just before leaving the house. The toilet,
shower and sink in this bathroom are the last set of fixtures before
the drains leave the house. The toilet is before the shower and sink
which wye into the main sewer pipe about 3 feet from the exterior
wall. There is a clean-out just inside the exterior wall under the
Third: My house has only one vent - the soil stack, which is in the
opposite corner from the bathroom. No fixture in the house has it's
own vent, and never has. Right or wrong, this has never been an issue.
All fixtures have always drained properly.
So, based on the information above, can someone explain why my toilet
has suddenly started erupting like Mount St. Helens?
I say that it has to be caused by an obstruction (not complete clog)
in the sewer from that point out to the street. More than likely
When a toilet upstairs flushes, a big slug of water travels down
the stack and past the basement toilet. Under normal conditions,
that slug doesn't fill the exit sewer and no significant pressure
builds to cause eruption. But clog the sewer a bit and the exit
*does* fill completely with no room for escape.
That's kind of what I thought. Now I just have to figure out if the
obstruction is in my section of pipe or the town's.
In years past whenever we had a backup, the town would snake from my
interior clean-out to the street and every time the clog was well out
into the town's section of pipe. A few years ago they replaced the
town's section with PVC and put a clean-out in the front yard so they
wouldn't have to come into the house anymore.
Now that the town's section is less than 5YO PVC and mine is still
cast iron, are the odds greater that the obstruction is in my section
- (i.e. my cost)?
If your section has to be snaked, and roots cut, I suggest the use of
copper sulfate crystals.
This time of the year the roots are really moving, this is the time
drop a couple into the commode in the evening, let them go into
solution, then flush it the next morning. Help the dissolve process
shattering a crystal before dropping it in the water.
You may be able to keep roots from being a problem after a root-
cutting down the pipe, without replacing the line. And it doesn't kill
the tree or bushes.
I would think most likely a partial obstruction has developed, most likely
somewhere upstream toward or in the vent. Check the vent for debris. A
properly installed and working vent is intended to prevent this exact thing.
Flushing a toilet injects a large slug of air into the line and if it does
not escape out the vent it will pressurize the line and blow water out of
the toilet and other traps.
One answer was slug of water hitting an obstruction beyond the toilet
and the next answer is a trapped slug of air before the toilet.
P.S. since posting my original post, I heard the BbbblewwERP and then
the sound of the upstairs toilet flushing, at least I know I should be
able to reproduce the problem.
What if I opened the cleanout in the basement, essentailly venting
that toilet. If the bubble still occured (or didn't) would that help
indicate where the problem was?
Not doubting you, but if the vent was clogged, wouldn't it cause
problems with other drains?
If this is a standard cleanout at approximately. waist level (no pun
intended), The water isn't going to have the impetus to travel 3 feet
up the soil stack, verses just slowly making it's way out to the
sewer. It sounds like you have a few roots growing into the clay or
cast lateral, and they are partially obstructing waste paper etc.
Large quantity drain dumps like a toilet or a clothes washer during
spin/drain should yeild the same phenomenon. Whatever you do, make
sure that the above toilet isn't serviced by the same stack with the
cleanout, or you will have one big mess if you flush it with the
The reason it's happening at your basement toilet is that it is the
lowest point in the drain system that has an air trap in it (cast into
the toilet bowl). The gallon or so of water held above this air break
is why you *hear* the gurgling of air escaping. You won't hear it
with other "vented" drains like the floor drain or shower/tub because
there is no above ground water to push out of the way in these cases.
OK. You do have an open (covered with grate) floor drain in the
basement also, correct? If the blockage ever gets bad enough, sewer
water will start to back up there onto your basement floor.
I haven't seen anywhere where you've tried a professional cleaning
yet. The ideal setup would be if your pipe is the same size from
cleanout to street, or if there is an outside cleanout installed
incase the pipe increases in size once it leaves the house. This way
the rotorooter guy can select a blade that matches the size of the
pipe and get more roots. Starting with a 4" blade inside the house
and going through a 6" lateral is fairly ineffective.
Also consider having them camera and videotape the lateral once
cleaned. You can tell what kind of obstructions and if there are any
flat points in the lateral that aren't moving water properly. Roots
and land movement over time can shift the lateral and sometimes heave
it upwards in one spot, causing a slow decline in functionality.
re: You do have an open (covered with grate) floor drain in the
basement also, correct?
No...there is no floor drain.
Update: Basement toilet overflowed this morning and water also backed-
up into shower stall through shower drain - while I was in the middle
of changing the brakes on the wife's car. Figures, doesn't it?
Town workers came and snaked thier section - no luck, not surprised
since it's fairly new PVC.
I used a flat snake with 2" diameter four-side arrow-like head through
the floor level cleanout in the bathroom floor. I managed to push
through an obstruction/clog about 40 feet from the hosue, which would
still be on my side of the town's cleanout.
Everything is draining but I'm still getting a bit of a gurgle in the
basement toilet. I'm going to cross my fingers and wait until after
Memorial Day to call a plumber and have it snaked with the proper
sized head. No sense paying holiday/emergency rates.
Thanks for all the suggestions.
re: Geez, that doesn't sound good, but I'm no plumber. Is the
basement floor finished, possibly covering up the drain?
Why do you say it doesn't sound good? I've lived in (and been in)
many, many houses with no floor drain. I guess it would convenient for
some purposes, except when the sewer backs up. Right now, a lot of the
back-up water stays in the shower base. With a floor drain, I assume
that all that water would end up on my basement floor.
re: Is the bathroom a remodel job or was it original from when the
house was new?
Both. The original shower (when I moved in) had no base, just a gasket
under the stall walls and a hole in the slab with a kitchen sink
strainer sitting in it. There was a toilet with a wall mounted tank
but no sink.
I have since remodeled by breaking up the floor and putting in a
regular shower stall with a base, a new toilet and added a sink.
re: Too small of a cable cutter will rarely affect anything longterm.
The call has already been placed to a highly recommended plumber, who
has me on his schedule for Thursday. In the meantime, I snaked again
last night and will do it again each evening. All I want to do is get
through each morning's sh*ts, sh*wers and sh*ves without an issue.
Final Update...I hope
Plumber came out today and found a mass of roots in the drain about 40
feet from the front wall. This is (coincidentally?) very close to the
junction where the town replaced their section of the sewer pipe with
PVC 3 - 4 years ago.
The plumber said that if the symptoms return, I should call the town,
explain the situation and ask that they check out the line with their
camera. It's possible that the junction has shifted and roots are
getting in. Otherwise, it could simply be a bad section of pipe on my
side of the junction, in which case any future repairs would obviously
be at my expense.
On Wed, 28 May 2008 10:28:20 -0700 (PDT), DerbyDad03
I don't recall reading about what type of trees you have. Consider
doing a "root prune" of the tree roots. Between the tree(s) and sewer
pipe CUT the roots a few feet back from the pipe.
One poster here puts salt down the drains to kill roots.
How far away from the pipe should I be concerned with the trees?
The only tree within 30 feet of the pipe is a small dogwood that is
about 10 feet away from the problem area and belongs to a neighbor. I
could probably prune the roots back a few feet and still stay on my
The roots that he pulled out were very fine, kind of a stringy mess.
On Wed, 28 May 2008 13:12:39 -0700 (PDT), DerbyDad03
Depends on the tree I guess. Not all roots are equal. A ficus will
seek water and invade the pipes. An Oak may just lift the pipe.
Prune them back, especially if they match the roots pulled from the
sewer pipe. I suspect the dogwood tree is doing very well! Enjoying
the gray water/ moisture from the pipe.
I don't think a small pruning of the dogwood roots would harm it.
What color flowers and how big is this dogwood <g>?
1. BTDT. Shoulda done a side deal with the contractor doing the work for
the city, and replaced all the way through your basement wall. Yard was
messed up anyway, etc, and some things are best done once and gotten
over with. In my case replaced all that old nasty iron and orangeberg
(don't ask, you don't wanna know) with nice slick PVC, and it was like
night and day flushing the toilets or running the washer. Any friends or
relatives with similar problems, I tell them 'pay now or pay later-
you'll end up replacing it all anyway'.
2, As to the floor drain the other fellow was asking about- around here,
those DON'T go into the sanitary sewers, they go into wherever the sump
pit and foundation drains go. Drywell or daylight drain, usually.
re: 2, As to the floor drain the other fellow was asking about- around
here, those DON'T go into the sanitary sewers, they go into wherever
the sump pit and foundation drains go.
No sump or foundation drains in my house. Sandy lot on top of a hill.
Never an issue with ground water or anything like that.
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