> A worn out flapper or ball.
> A damaged seat under the flapper.
> A damaged gasket under the flush valve.
> A hole or crack in the overflow tube.
> A refill valve (ballcock) that needs a new seat or washer.
~Signs of a leak.~
There are a number of signs that a toilet needs some repairs, but manytoilets leak without conspicuous indications of trouble. Here are some of the more obvious signs of a leaking toilet:
*** If you have to jiggle the handle to make a toilet stop running.
*** Any sounds coming from a toilet that is not being used are sure signs of leaks.
*** If you have to hold the handle down to allow the tank to empty. This can also mean the chain or strap is too long and doesn't lift the flapper or ball high enough to float on its own.
*** If you see water running over the top of the overflow, you definitely have a leaking refill valve. If you are unsure whether or not water is running over the top of the overflow pipe; sprinkle talcum powder on top of the water in the tank, and you can clearly see whether or not it is.
*** If you can see water trickling down the sides of the toilet bowl long after it's been flushed;
*** If water drips out of the refill tube into the overflow pipe;
*** If a toilet turns the water on for 15 seconds or so without you touching the handle, this is otherwise known as the phantom flusher.
~~The Dye Test~~
However, even if your toilet doesn't have any of these symptoms, it's still possible that it is leaking. These leaks are known as SILENT LEAKS, because they usually go undetected. There is an easy test you can do that will positively tell you whether or not your toilet is leaking. And if the test shows that the toilet is leaking, there is a second test that tells you what part inside the tank is responsible and needs fixing.
Remove the cover on the toilet tank and carefully set it aside so it can't be accidentally knocked over and cracked. Remove any "in-tank" bowl cleaners that color the water and begin the test with clear water in the tank as well as in the bowl.
You'll need some dye. Some municipal water companies will provide dye capsules or tablets, but food coloring or instant coffee works fine. Now put enough dye in the tank water to give the water a deep color. Wait 30 minutes and make sure nobody uses the toilet. In 30 minutes if you find any of the dyed water is now in the toilet bowl -- your toilet is leaking. A properly operating toilet will store water in the tank indefinitely without any water running into the bowl.
Water on the floor around a toilet is certainly a problem. It can be dripping off a sweaty toilet tank during humid weather; it can mean the wax sealing ring under the bowl has disintegrated, or the bowl is cracked; or it can mean the connections under the tank are leaking. So for now, let's say you've done the dye test and found your toilet is leaking, you now have to find out which part is the culprit ... the flush valve or therefill valve. And there's another simple little test that points to the perpetrator of the crime.
Draw a pencil line on the back wall of the tank on the inside of the tankat the waterline. Then turn the water supply off, either under the tank or at the main shutoff ~~ wait 20 to 30 minutes. If the water level remains at the pencil mark ~~ the leak is occurring at the REFILL VALVE, the unit in the left side of the tank. If the water level falls below the pencil mark ~~ the leak is in the FLUSH VALVE, the unit located in the center of the tank.
Most of these repairs can be done by the average homeowner at minimal costs. Local hardware or home improvement centers sell "kits" with all the interior parts of the flush valve assembly and easy to follow instructions at very reasonable prices.