We've lived in our 90-year-old home for 4 years. We have a basement
bathroom with shower, toilet, sink. The bathroom is on an 18-inch
Last New Years Eve, water flooded the basement from underneath the
bathroom, probably 20-30 gallons. We suctioned it out, no further
problem. A few weeks later, it did it again. A few weeks later,
again. At this point we called plumbers out to take a look, and they
could find nothing wrong, and had no explanation for what was
A few points:
1) The water is cold, not hot. My first thought was the water heater
(which is also in the basement, in another area) had spilled, but
that's not it.
2) The water is clean. There is no smell or debris in the water. (No
toilet overflowing, etc.)
3) It floods all at once. We checked for some kind of leak that might
be building up, but there was none.
4) The flooding happens at night (or very very early morning), so the
water is not in use at the time it floods.
5) The flooding is irregular; that is, we can't predict when it's going
6) We had not had the problem for 3 1/2 years....why did it start now?
No construction or anything like that going on.
We need some advice on how to stop this flooding; it stumped our two
plumbers (who seemed competent in all other ways.) Thanks for any
You say cold, not hot; but do you really mean cold (as in fresh from the
tap) or simply "not hot" (i.e. room temperature)? If the latter, are you
certain you have found the flooding soon after it happened, or is it
possible you're finding hot water that cooled down?
Any correlation with weather (e.g. rain)?
Any correlation with the use of the facilities (shower, toilet)? For
example, any chance there's some shower overspray that's collecting
somewhere to dump when it reaches a certain level? (I had a really weird &
hard to trace leak problem that turned out to be something similar. The
shower leaked when someone was using it, but not when no one was in the tub.
That one took me a couple weeks to find. <g>)
Have you actually witnessed the flooding?
Is 20-30 gallons perhaps an overestimation? Any chance it's the same amount
of water that's normally in the toilet tank? Does the toilet run during or
after the flooding incident? Does it happen quickly (say, in a minute) or
does it take a few minutes or hours?
Do you have young kids who might know they're doing something to cause this
but are afraid to fess up?
I'm mostly stumped too, but I have to think the toilet is suspect #1 if it's
coming from the bathroom platform. I don't know what might cause it,
Several good responses, I appreciate all of them. Let me address some
of the points, expand a bit on the original post.
1) The water is "cold" to touch, but bare feet are not good
thermometers. We have two sons whose bedrooms are in the basement, and
they caught the water mid-flood a couple of months ago. The water was
flowing from under the bathroom platform, and the water was cold, not
hot. The water heater was the first thought because of the pressure
release valve, but it's located in another room 25 feet away. Some
water seeps into that room, but looked like it was water spreading from
the point of origin in the bathroom area.
2) The amount of water was based on a half dozen or so dumpings of the
shop vac used to suck up the water; i.e., 3-5 gallons per load x 6
loads = 20-30 gallons of water. This amount has been consistent.
3) No correspondence with weather at all. New Years Eve night was cold
and dry here. Another time it had rained the night before.
4) No correspondence with water usage, other than it's when water is
NOT in use anywhere in the house, very early in the morning. The
plumbers checked for leaks from the shower, and around the toilet
(which I had already done.) The flooding appears to happen very
quickly, within a few minutes. I'm also pretty confident it's not
kid-related. Our kids are teenagers, and the boys, who have best
access to the bathroom, are the ones who clean it up every time. (We
even keep the shop vac downstairs for them. LOL)
5) Have already thought of the flood alarm, but the chlorine tester
might be a good idea.
Thanks for the brainpower guys, I've run out of ideas, other than
overhauling the entire bathroom. I really believe that the sudden
onset of this problem holds the solution. Just wish the pros had been
able to figure it out.
So, you have a bathroom IN the basement, not above it, which is built
up on a platform underneath which the water flows. What is under the
platform? Do you have a pump to move waste water UP into the sewer
line? What exactly is the situation with the bathroom setup in the
Phil Munro Dept of Electrical & Computer Engin
mailto: firstname.lastname@example.org Youngstown State University
It sounds like probably water is backing up and coming out the lowest
drain in the house. Based on the timing and the volume of water, a
couple possibilities are: (a) sump pump discharge, or (b) water
softener discharge. The water softener in particular would probably be
set to cycle during the wee hours. If you have either of those things
you might want to have them checked out. Note that the problem may be
that your house drain is blocked somewhere downstream and this is just
the event that shows it because water is put in the system faster than
it can handle. Although I would think that draining a bathtub full of
water, say, or washing machine discharge would do the same thing. -- H
First off, recommend not going into unknown source water with bare
Is there any water on top of the platform when the flood happens? If
so, I would be looking for the source at or above that level and in the
vicinity if the platform.
I like the sump pump idea, is there a sump pump and where does it
Get a chlorine test kit and the next time it floods check the water for
Cl. if it extremely low compared to normal tap water the source is
most likely condensation or maybe rain. In my case it was condensation.
Not as big a problem as yours but big enough. The water would suddenly
come out from aound a pipe in the ceiling of the garage which was under
the house. Old vinyl floori covering was creating a kind of valve that
would allow the water to build up then suddenly empty. toilet and
shower were on a platform. I guess this was so you could get the car in
the garage. Problem was cured when bathroom was overhauled and garage
was dug lower. The platform was removed and the plumbing was run in the
garage. Rguardless of what is wrong you will probably have to rip out
at least part of the platform to fix it.
That is a real mystery. Any chance the city main sewer is clogged or
overflowing occasionally and backs up your toilet? We had a sewer
problem that showed up in our condo first because we are the closest to
the city main sewer line. Both toilets began backing up and initially
there was sewage in the puddle but then it seemed cleaner. First thing
I did was to ask other neighbors if they had problems, and initially
they said no, but everything was coming into our unit so they didn't see
any backup. Then I called the city (Sunday evening) to see if there
were problems downline. Nope. Then we got a plumber to ream out all
the way to the city main, about 300'. Nothing of note pulled out.
About a week later, the city was excavating right where the sewer line
from the condo joins the city's main sewer line. There are also pumping
stations for sewage on the city side to get it from here to town.
Maybe you just have a bad seal and if the city's lines are overloaded
you get some back pressure occasionally?
Perhaps what you are seeing is the result of a sump pump with a deteriorated
out put hose. The reason it doesn't happen all the time is that the pump
would only come on when the water in the sump reached a certain level. This
might also account for the 20-30 gallons, as most sumps that I have seen are
not much larger than a small trashcan (32 gallon).
Interesting problem. Please keep the group informed.
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