How do You Stop a Toilet from Running?

You may need to replace parts of the flushing part of the toilet to get it to stop running. While it’s running, remove the cover to the tank and see what is happening. The part called the ball, that has a rubber part is usually not dropping and covering the opening when it is supposed to. Flush the toilet while you are watching to see what is happening. The hardware store will have any parts you may need.