Toilets have five washers. Two are located at the screws that secure the tank to the base, one where water from the toilet tank flows into the toilet when it is flushed and one in the fill valve. There is also a shank washer. If water is leaking out onto the floor, it may be coming from one of the washers located around the screws that hold the tank to the base, the centre large washer or the shank washer. If the fill valve does not turn off all the way and water is trickling out of the overflow tube, replace the flush valve washer.
Turn off the water to the toilet by closing the valve located at the base of the toilet tank. Remove the toilet tank lid.
Flush the toilet and hold down on the handle to allow the tank to drain completely. Remove the remaining water by absorbing the water with a sponge and wringing the sponge into the sink or a bucket.
Replace a shank washer by unscrewing the nut located on the water supply line. Lift the shank out of the toilet tank. Replace the washer. Place the shank back in position and replace the nut. If you're replacing only the shank washer, skip to Step 7.
Hold a screwdriver on the screws located at the bottom of the tank on each side of the flush valve and turn the nuts located underneath and outside the tank. Gently lift the tank off the base.
Replace the washer located at any of the locations where there was a leak. Replace all three washers if there are signs of wear, such as cracking, on the washers. Place the tank.
Push the bolts through a washer and then into the holes to hold the tank to the toilet. Replace the nuts and tighten the screws. Do not overtighten, or the porcelain will crack.
Turn the water back on and check for leaks. Tighten the bolts slightly if there is any water leaking around the shank washer, tank bolts or beneath the fill valve.
Remove the toilet tank lid. Take the top off the fill valve. It will twist off, or there will be two screws holding it onto the base of the fill valve.
Remove the washer from the fill valve. Remove any build-up of minerals located in the valve. Place the new washer into the fill valve.
Reattach the top of the fill valve to the base of the fill valve. Replace the toilet tank lid.
A leaking washer on the base of the toilet tank may not be noticed right away and may saturate the floor, causing a lot of damage. Check toilet washers periodically for signs of cracking, and replace them before the toilet leaks. Take the old washers with you when you go to the store to be sure you purchase the correct size washers.