One of the overflow pipes from the water tank is dripping (has been for a few weeks now). I've been in the loft and can see 2 pipes going out but the 1 that is dripping doesn't seem to be coming directly from the tank. The water level is just below 40 gallons. I'm struggling to get round the tank to work exactly where this pipe is leading to so before I risk my life and look round, does anyone think it might be the float valve?