Ask a Tradesman
I live in a flat 1 up. The overflow pipe is running outside my neighbours. My bathroom isn't on an outside wall it's all internal. I don't think it's my cistern that's causing the problem although I have had a letter to say it's someone on the first floor that's causing the overflow. I've checked my cistern and it doesn't look as though it's overflowing. I suspect it's my neighbour as the overflow pipe is outside her bathroom. Is there anything else it could be if it's me that's causing the overflow pipe to run.
If you have a hot water tank it could be that, other than that you should turn off the water supply to your flat and leave for about 5 mins. If the overflow stops it will be your flat, if not then it is a neighbour.
Answered 5th Dec 2012