How to fix a running toilet is one of the easier plumbing issues.
You would be shocked to find out how much water a running toilet can waste! Would you believe two gallons of water per minute, and a toilet leak can waste up to 7,000 gallons of water per month.
Take the top of the tank off and check if the chain that is connected to the flapper and if it is the right length? If it’s too short it will prevent the flap from sealing properly, and a chain that is too long will often get in the way of the seal.
If the chain is okay, most likely you need to replace the flap assembly in your toilet tank.
Before you begin to work on your toilet, turn off the water by turning the valve on the wall behind your toilet clockwise. Flush your toilet once to empty the tank.
Next remove the flap assembly from inside the toilet tank and take it to your local hardware store. They will be able to help you with a replacement.
Bring the flap assembly home. Install it in your toilet tank, no tools required. Turn the water valve back on and you should be good to go.