Suspected backflow from flat waste drain - help!
Drainage and wastage systems and plumbing help, advice and answers

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Suspected backflow from flat waste drain - help!

Post by cynic » Sun Feb 22, 2009 3:11 am


I'm a newbie and have trawled the site but can see my little drama on here. So i'm hoping some of you guys can shed some light and help me.

-I live on the ground floor of a 3 storey block of flats (shared ownership)
-my kitchen floor and underneath kitchen sink is being flooded by dirty looking water (but often discover it in the morning when I've not been using anything at night)!!

-I unscrewed all fittings and pipes under sink that were'nt sealed and there is no obvious blockage
-had a handyman around (he ahhhed and ummmed)
-had my dad inspect

-kitchen floor and under sink often soaking wet in AM
-this happened once 6mths ago and I just thought my mate had buggered something up in kitchen
-last weds it did it again, then this morning
-the w/m tube is connected to a vertical plastic pipe (looks like the weak link)
-have put soda crystals down sink and ran washing machine on a rinse with them in which flooded my kitchen from backflow up vertical w/m pipe
-also water bubbled and erupted into both sinks
-no major probs with my toilet

-near the end of the machine cycle (10mins to go on a 30min wash) there was vibration in w/m vertical pipe and the water erupted from the top of the hose (which is only in partially as it has 'two hands' to fix it )
-my piping is like this ... 2 sinks main and sml on left
-piping straight under main sink with D shape connection pipe too
-then main foot long horizontal pipe
-that connects the u bend that links the vertical pipe to w/m hose
(I can post pics if that helps?!)

I also opened both viewing chambers outside and 2 side of flat. Worked out which was mine and they both looked clear (big long chimney type things with 3 tunnels at bottom )

-today discovered that if my upstairs neighbour runs water into her sink it comes out of my left hand side pipe (discovered as Dad was trying to screw it back on when it happened)
-defo looks like it's not a blockage in my sink

-could it be that the waste pipe to the main drain to me is blocked and that is why i'm getting backflow?
-i'm really worried that if all the peo in my block use the w/m at night i'll wake up afloat on my bed!
-rang housing association (I part own property) and they really seem not bothered
-I've stressed it just happens to be me that has the problem but I suspect it's somewhere in external pipes as the backflow when I used the washing machine was long in coming
-my next door ground floor neighbour has no probs
- I do use calgon to reduce limescale in wash machine
-i've put a sign up in flats asking anyone else to say if their having a prob too so we can ambush the housing ass to investigate (e.g I can't get dynarod etc in as it's not my external property to go routing around)
-if so what is the solution? (there's no way to see where pipes are going they go to left into wall leading to communal hall I think and disappear in a wall)?

It's a 4 year new build Bellway property in London

Any advice? Sound like a common problem? relatively easy to fix?
My reponsibility or water board??

Any thoughts or questions v welcome as I'm getting worried all the flat's waste is coming back up into my kitchen

ta :?

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Post by stoneyboy » Fri Feb 27, 2009 6:33 pm

The chances are that you have vertical stack which runs through all 3 floors and that the base of this stack has an obstruction. Open the inspection chambers and see what happens when you run the washing machine - does it look as though the flow is restricted.
I would think the chances are that you will have to get specialist help in tracing the problem.

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