This problem is driving me nuts! The top tank for the hot water overflows at night time but is OK during the day. My conclusion is that there is a very slow leak when it should have shut off. I have bought 3 new valves. Took the first one back as defective, next one has same problem. Bought from another source - same problem. Our water pressure is very high . Could that be it? Any ideas? Would be most grateful. Fed up with wasting water and the drip drip drip from the overflow - torture! Thanks

1 Answer 1


The high water pressure could very well be causing the slow leak. Float valves rely on the pressure of the float to close a small valve in the stem. High pressure could allow for a little water to work its way through. A quality fill valve should be able to handle it. The fluidmaster 400 ARHR is a great low cost fill valve. You could also try a commercial fill valve. They are built to higher standards.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.