Check the tank water level. It should be 1 inch below the overflow. If that's not the problem, add some food dye to the tank water (NOT fabric dye). If it shows up in the bowl, replace the entire flapper valve assembly including washers. If not, replace the entire fill valve assembly. If that does not eliminate the leak, call your plumber.

Hi, You changed the fill valve and developed a leak. If you didn't

have a leak before you changed the fill valve my guess is you put the tube from the new valve into the over flow pipe. That will cause the problem you have it is siphoning water out of the tank. Use the hardware that came with the new valve, connect the hose from the fill valve to above the overflow pipe.

Good Luck Wood Butcher

just call a licensed professional and save yourself time and money!!