is it the overflow from the toilet cistern or the cold water tank?? should be the same solution except the toilet one is usually easier to get to. have a look inside: there's a stick with a floating ball at one end and a valve at the other. what's probably happened is the valve has worn out. if its a metal stick you may be able to bend it so that the float sits lower in the water.  if its a plastic stick then there will be a little plastic screw somewhere to adjust the angle where the stick attaches to the valve or the stick attaches to the ball. this will either fix the problem for a while, or give you a longer snooze time before it starts to overflow after running the tap or flushing the loo.

a new ballc*** valve system is going to cost less than £8 from b&q and i'm sure any alpha male with a toolbox will come and fit it for you if you ask nicely....

my dh is a plumber and says u need ur ballc*** changed in ur tank. hth saz xxx

strange thing to be talking about on a parenting website but i'm clueless and fed up. my overflow runs every single night from about midnight, i run the cold tap for a few seconds to stop it but sure enough it goes again less then half an hour later, last night i was awake till 4 as it kept going every few minutes leaving me not enough time to doze off, its right outside my bed window,and its like water torture!lol. i ended up sleeping on our 2 seater sofa, which as 7 months pg is not comfy let me tell you. our  estate agent has had it reported to them 3 times and havent sent anyone so ive had enough. any ideas?