Toilet leaks are leaks in which water from the tank seeps into the toilet bowl. From there, the water goes into the sewer system. If you can hear the toilet running or need to jiggle the handle to get it to stop running after you flush, you have a toilet leak. Sometimes you cannot hear the leak, however. To determine if you have a leak, place a dye tablet or food coloring into the tank and do not flush the toilet for about an half an hour. If the dye coloring has seeped into the stool from the tank, the flapper is leaking and needs to be replaced. Local hardware stores carry new flappers for about $5.00, complete with installation instructions. If you have more than one toilet, either do the dye test for all of them, or turn the toilets off one at a time, and do the overnight reading again. This may take a few nights to work out. Click here for more information about common causes of leaks.