Locate the shutoff valve behind the toilet near the wall or floor
Turn the valve clockwise until it stops
If there is a lever handle, turn it a quarter turn so it is perpendicular to the pipe
Flush the toilet to drain the tank and stop refilling
If the valve is stuck, gently use pliers or a wrench to turn it clockwise
If there is no local shutoff valve, turn off the main water supply to the home
Confirm the water has stopped flowing into the toilet tank