Sometimes you can hear the toilet running. There are also leaks that are considered silent toilet leaks. Here are two visual tests that you can do to help you check your toilet for a leak.
1. Dye Test – Flush the toilet and wait 5 minutes for it to refill. Remove the back of the toilet tank cover and put several drops of food coloring to color the tank water. Do not flush the toilet at this point. Check the toilet bowl every 10 minutes for the next 45 minutes. If any colored water gets into the toilet bowl, then you have a leak in the toilet. Flush the remaining colored water through. You need to fix the toilet.
2. Stand tube test – Flush the toilet and wait 5 minutes for it to refill. Remove the back of the toilet tank cover. Sprinkle some powder on the top of the water. If the water level is too high, you will see the powder on top of the water drain down into the stand tube. This is a silent type leak in your toilet. You will need to adjust the water level to ½ inch below the stand tube.