kitchen drainage

[bombles]

help. everytime i empty the kitchen sink of water it ends up coming up the washine machines overflow pipe (all connected together to via piping and a u-bend). have tried caustic soda etc but nothing works [/code]

 

[JPC]

take the pipework apart and clear it out

 

[Gary_M]

On my washing machine emptying hose there is a little flap of rubber that works as a one way valve - allowing water out of the machine, but nothing returning to it.

Something like this would work too, but I agree that things probably need cleaning too