Toilet leaks occur in two ways and are often very difficult to detect. First, the most common toilet leak and often hardest to detect is caused by a deteriorated or defected flush valve (flapper) or “tank” ball at the bottom of the toilet tank. If the flapper or ball valve does not seat properly and form a water-tight seal, water will leak around it into the toilet bowl. Often, this leak will occur without being heard. Here is an easy way to check for flush valve leaks and in just minutes, you can find out if a toilet is wasting thousands of gallons due to an undiscovered water leak. Remove the tank lid, then flush. After the flapper/tank ball drops and the tank refills, add several drops of dark food coloring) or a Fluidmaster leak detector tablet. Wait at least 20 minutes. If any trace of color appears in the toilet bowl, there is a leak.
The second most-common type of leak is caused by improperly adjusted or broken fill valve. If the float is set too high or the shut-off valve fails to close completely, water will continue to enter the tank and flow into the overflow tube. This type of leak can be seen simply by taking the tank top off and observing if water is flowing into the overflow tube once the tank is full. Excess water pressure can also have a negative effect on the operating system in your toilet. If you are experiencing either of these types of leaks and do not know how to fix them, contact a plumber.