If you have replaced the flapper in your toilet tank and water is still seeping out, it is most likely time to replace the flush valve.
Step 1: Use the shutoff valve to turn off the water supply to the toilet. Flush the stool and soak up the excess liquid from inside the tank with a sponge. Disconnect the water supply line beneath the tank and use an adjustable wrench to loosen and remove the two or three tank-to-bowl nuts and bolts.
Step 2: Carefully lift the tank up and away from the back of the stool. Remove the tank to bowl gasket from beneath the tank. If it is worn, now is a good time to replace it. Thoroughly clean the bottom of the tank and the top of the stool to assure a tight seal when you replace the tank.
Step 3: Remove the existing flush valve and replace it with the new flush valve. Push down on the flush valve as you tighten the retaining nut on the underside of the tank.
Step 4: Replace the tank to bowl gasket and reattach the tank to the stool. Make sure the tank is well-seated on the stool before tightening the tank-to-bowl nuts and bolts.
Step 5: Attach the fill tube to the top of the flush valve and attach the flapper chain to the flush handle.
Step 6: Reconnect the water supply line to the bottom of the tank and turn the water supply back on. Check for leaks and make any necessary adjustments.
Step 7: Flush the stool to make sure the flapper chain length is long enough to allow the flapper to seat properly, but short enough to keep the lever from hitting the tank lid once it is replaced.
Step 8: Replace the tank lid and give the stool one more flush for good measure.
Now put away your tools, recycle the old flush valve, if possible, and relax knowing your water dollars won’t be draining away anymore.