Why is my toilet leaking underneath?

Answer 1

This is caused by a flush valve that is not closing completely when the tank is full. The flush valve closes when the large float in the tank rises to the top as the water fills the tank. The float is often at the end of a soft metal rod about a foot long. Bend this rod downward just a bit and the valve should shut off properly.

If the float is a sliding type found on many newer low-flush toilets, I have no suggestion other than that something might be caught in the assembly, or perhaps you will need to replace the entire flush valve.

Answer 2

The wax ring underneath was probably not thick enough to start with or one of the bolts holding the toilet down has rusted through letting the toilet rock and break the seal. Very easy and cheap to fix. Turn the water off, disconnect the supply line to the tank, flush the toilet and hold the handle down until all the water is out of the tank. You can use a sponge or towel to get what is left in the tank. Remove the nuts on the bolts holding the toilet down. If there is a tub next to the toilet and you are strong enough, put a towel or piece of cardboard in the tub so it will not get scratched and lift the toilet straight up and set it in the tub. You can also set it in a pan big enough for the base. Tip it forward and then back to get the water out of the bowl and trap. The old wax ring is on both the bottom of the toilet and the floor drain. Remove as much of the old ring as possible, it doesn't have to be perfect. If the floor flange is level with or slightly above the level of the floor, a standard wax ring should be thick enough. If in doubt, use an extra thick one, any excess wax will just push out from underneath. I usually put the new ring on the floor drain instead of on the bottom of the toilet. Make sure the two bolts are standing upright and set the toilet straight down over the drain. You should be able to stand in front of the toilet and lift on the bowl between the seat and the tank. Once the toilet is in place, lean on the toilet in the same place to compress the wax ring. Install the washers and nuts on the anchor bolts and you're done. A wax ring is $3 to $5, a lot cheaper than calling a plumber.

Answer 3

If the rubber seal between the bowl and tank is fine, or the rubber washers holding the tank to the bowl is fine, the problem could be the tank is sweating. This is caused by the warmer ambient temperature on the outside of the tank compared to the cold water inside the tank. This causes sweating on the outside of the porcelain. A way to prevent it is to get a lined tank for the toilet. It has Styrofoam on the inside which will prevent the sweating on the outside.

Answer 4

From where ever the water is coming from: Inside? outside? underneath. I can't see it from here.

Answer 5

Adjust water level in the tank and/or replace rubber flapper.

Answer 6

How can I do some home toilet repair? I have an upstairs pipe that is leaking underneath the toilet.