To determine if a leak is located inside or outside your home, you will need to locate and turn off the main water valve for your home. This valve is usually located along an outside wall in your basement. By turning off the main water valve, you will prevent any water from flowing into the property. This will isolate the source of the leak as being inside or outside your residence. Take a meter reading and wait an hour and retake the meter reading. If there is no change in the reading, then the leak is inside. If the meter changed, the leak is somewhere between the meter and the main water valve.
Leaking toilets are often hard to detect and are one of the most common water leaks in the home. Toilet leaks can waste hundreds of gallons and oftentimes cannot be heard. Even a small toilet leak can waste a considerable amount of water and money over time. Most toilet leaks are easy and inexpensive to fix. One way to find out if you have a leaking toilet is to place a drop of food coloring in the toilet tank. If coloring shows up in the bowl sooner than 10 minutes without flushing, your toilet has a leak. Make sure you flush to avoid tank staining.