There are a number of potential red flags that you may have a leaking toilet tank. The first is constantly hearing your tank running. Your tank runs a lot if you have a leak because it has to replace the leaking water. The next is a higher than normal water bill. If you hear your toilet running, and then get a higher than normal water bill, there is a good chance you have a leak in the toilet tank. However, if you want to confirm for sure that you have a leak in your toilet tank, follow the steps below:

1. Take the Lid Off of Your Toilet Tank

The first step is to take the lid off of your toilet tank. If you do not know where the tank is, it is the rectangular piece that is raised upward behind the toilet bowl. The lid will simply lift upward, allowing you to see into the tank of the toilet. 

2. Observe the Water in the Tank

When the water is not refilling in the tank, take a few minutes to watch the water. The water should be still. If you see ripples or bubbles in the water, that is a pretty strong indicator that you have a leak. These ripples or bubbles are caused by moving water, which should only happen when your toilet is flushed. 

3. Dye the Water

To positively confirm a leaking toilet, dye the water. This can be done by adding a few drops of food coloring to the water. If you don't have food coloring, you can add a bit of Kool-Aid Mix to the water. You want to add enough dye so that you can easily tell that the water is colored and not clear. 

4. Wait an Hour and Check the Bowl

Let an hour pass by. During this time, do not allow anyone to use or flush the toilet. After an hour has elapsed, look into the toilet bowl. If the water in the bowl is colored, you have a leak. If you think you see some color, but are not positive, or you do not see any color in the bowl allow another hour or two to lapse. It may take a slow leak longer for the color to pass to the bowl. If you do not notice a dye transfer after a few hours, you do not have a toilet leak. 

If the colored water disappears from your tank, you do indeed have a leaking toilet tank. Unfortunately, locating the source of the leak and fixing it is not an easy task. Once you have determined that you do have a toilet tank leak, you will want to call in a plumber to determine where the leak in the tank is and to repair the problem. If you have other toilets in the house, turn the water supply valve to the off position to prevent wasting any more water. 

Check out a website like http://www.garabedianplumbing.com for more information and assistance.