We've recently noticed a leak under our sink - it's possibly always been there and it's just not been severe enough that we've noticed it. The system was fitted by the previous owners of the house and we moved in about 4-5 months ago
From what I can see then black flexi pipe is venting from the main waste pipe after the bend. This pipe appears to have no valve fitted and is currently brimming with water.
Has anyone ever seen a similar system? Any advice on what needs to happen next to get this fixed? Just looking for a bit of information so that I know if I'm being fleeced by my local plumber if/when I call them out.