A leaking hot water tap also wastes costly energy. Because this leakage can occur almost noiselessly, dye testing is a more reliable means of detecting internal leakage. Wait 10 to 15 minutes. If color appears in the trap, the flush valve is leaking. Check the flush valve seat for corrosion or scale and make sure the flush valve ball is aligned with the valve seat.
Valves are available at most hardware stores.
A leaking flush valve permits hidden internal toilet leakage. Dye testing procedure for internal toilet leakage. Place food coloring in toilet tank. Wait 15 minutes. Color appearing in toilet trap signals a leak.