Although it is one of the most useful important parts of your home, the toilet is probably by far the simplest to understand. It is made of only a few working parts that are easy to maintain and repair. Each of these parts is located inside the toilet tank. If you open it up you will see a flapper at the bottom of the tank, When you flush, this flap opens to allow the water to drain out. Sometimes some grit or other debris will get around the flapper opening causing it to not seal correctly. This makes your toilet run constantly. When the toilet is filled with water, a float mechanism turn off the water. It’s a simple as that.