Plumbing question - I can't figure out where the water in my bathroom sink goes!

M

Monbretia

Registered User
Messages
2,642
This is something that puzzles me regularly but today I decided to really test it. So I have a bathroom in front of house, main bathroom even though it's mainly just the shower in there that is used. Anyway the drains run along the front of the house with a manhole at either gable and another one stupidly under the paving slabs in the porch outside this particular bathroom window. It can be accessed in emergencies but not easy!

Anyway if I lift the manhole at farthest end of house and flush toilet water goes through manhole, same if I turn on shower but if I run the sink no water appears in the manhole drain, the sink does empty, it doesn't appear to be blocked although it does get empty slower than it fills if you follow. Today anyway I filled it to the brim with very purple water (using up a bottle of old food colouring) and then pulled the plug and went out to watch the drain, absolutely nothing appeared.

Should it be draining in there? I can't imagine where else it should or could be going, where should I start looking to figure this out. There is no sign of damp patches anywhere either in bathroom or porch.
 
Checked that, it's not coming out there either, that goes into same manhole at the end that I'm checking.
 
Did you try running other taps/showers after emptying the sink to rule out some temporary point ?
 
I will try that in the morning from the other bathroom which should go into same pipes. Kitchen is other side of house so nothing from there goes that direction.
 
Well I discovered nothing today anyway! All 3 bathrooms are on same side of house pretty much and feed to same manholes, when I run taps/bath/shower in the other 2 bathrooms the water appears in the pipes as it should. Having gone back to turning on the mystery tap I checked every water outlet under downpipes etc all around the house just in case and there is not a sign of that water coming out anywhere.

At this stage I am convinced it is just flowing into the earth somewhere under that bathroom or more likely the porch outside it where the only other manhole is, I may just have to pull up those paving slabs and have a look at that one, I have accessed it before but it's a nuisance as the cover can only be lifted slightly and not fully removed.
 
I wonder is the pipe broken and the water just soaking away into the soil?
 
That's what I'm thinking at this stage :(

My father's driveway has developed a mini sinkhole from a similar problem, turns out a drain from a small conservatory which runs under the tarmac drive to another drain had obviously broke at some stage and water was draining nowhere but under the tarmac close to the drain and it all collapsed into about a 2ft deep/wide hole last week, probably going on for years but it just made me wonder all over again about my bathroom sink. Luckily no one drove over that spot recently! Sometimes when I pull a little cart I have with bags of compost for example across the paved porch area there is a very hollow sound in one part! :eek:
 
We have a downstairs toilet with tiny sink. We were told after the builders had vacated the site that the water from our sink was draining in to the soil outside. We have lived in the house for 25 years and just use the sink occasionally. It has never been a problem but I often wonder if there is a problem waiting to happen.
 
@Montbretia do you live in a subsidence area? If not you’re probably OK. I live in a subsidence area and we replaced all the old clay sewer drains as leaks could have led to problems over time.
 
Not that I know of, this is a relatively new estate, 30/35 yrs old so don't know what sort of pipes were in use then, never heard of any issues in the area anyway. I had an excellent builder but of course you never know!
 
OP, you could try a smoke test to see where the drain terminates.
I've done it successfully before using a good / powerful smoke machine. Very effective
 
Where does the rain water from the downpipes go? You may have soak pits that they empty into and the sink water may be piped into one of them.
 
Goes into the main drains too, don't have soak pits that I know of, I'd know about that surely. All the other bathroom sink/shower/bath water goes to the main drain other than just this one. Certainly along the front of the house where the manholes are I can see that the downpipe water is emptying into these same drains.
 
You must log in or register to reply here.
Back
Top