Potential leak from waste water pipe?

[Clares2911]

I live in a ground floor flat and each time I use my washing machine or dishwasher I notice that my laminate flooring in my hall raises unevenly and in the hall cupboard behind this bit of flooring there is a damp patch on the chipboard flooring-I'm guessing that this must be my waste water pipe leaking? Would that sound about right? And if so what is the best way to tackle?
Thanks!!

 

[Burnerman]

There's no easy way to say this, but its time for that floor to come up.....and if its been leaking for a while, expect disaster chipboard wise - it just doesn't like getting wet, and swells dramatically.
John