Toilets receive a lot of use in homes, making them prime candidates for mechanical malfunctions. The majority of working toilet components reside in the tank behind the bowl. Toilet tanks that do not fill up after flushing can be caused by a number of different problems. Fortunately, even a novice repair person can diagnose the problem and make repairs to keep the toilet in good working order.
Check to ensure the water is on to the toilet. In most homes, you will need to turn the wall valve counterclockwise to turn on water to the toilet.
Remove the toilet tank lid. Ensure the flapper on the tank bottom closes. If the chain hangs up in the tank, it will prevent the flapper from closing.
Look for water coming out of the tank fill tube. Low or no water can indicate the fill valve has a clog. If this is the case, you most likely will need to replace this unit.
Test the float. If the float is stuck, it can limit the amount of water entering the toilet tank.