Adjust the fill valve

Step by step

1. 1
   Look at the water line

   The water should sit about 2 cm below the top of the overflow tube.
2. 2
   Lower the float

   On a modern fill valve, twist the adjustment screw or pinch the clip and slide the float down.
3. 3
   Flush once

   Watch it refill. If it still hisses, the flapper is the more likely cause.

Did this fix your problem?

FixNShare uses real results to help the next person find the repairs that actually worked.