It's estimated that 20 percent of all toilets leak. Even if you can't hear the leak, you could be losing up to 200 gallons of water every day!
Many toilets in Santa Barbara leak overnight when the water pressure rises. This happens when the water level in the toilet tank rises above the overflow tube and runs down the tube constantly.
Not all universal flappers are universal, and a mismatched flapper can result in gallons of undetected water waste per flush. To check this, you will need to look inside the tank.