Fixing leaks in your home can reduce your monthly water bill as much as 10 percent. Leaks most commonly appear in toilet flappers, faucets and valves. A deteriorated toilet flapper is one of the most common causes of toilet leaks. The flapper is a piece of rubber that covers the valve connecting the toilet tank to the toilet bowl. Over time it can crack and have buildup on it that prevents it from sealing properly. One way to tell if it’s leaking is you will hear the toilet tank fill up constantly and flushing. If you don’t see or hear anything there is a simple way to confirm if the flapper is leaking. Put a few drops of food coloring into the top of the tank and wait about 30 minutes and if the color has gotten into the bowl then your flapper has most likely failed. Replacing a failed toilet flapper is fairly easy and likely qualifies as a DIY project.