Faulty Flapper – The rubber flapper at the bottom of the tank controls water flow into the bowl. If it's worn out or misaligned, water will continuously leak.

Improper Chain Length – If the chain connected to the flush handle is too short, the flapper won’t seal properly. If it's too long, it may not lift the flapper at all.

Faulty Fill Valve – The fill valve regulates water flow into the tank. If it’s malfunctioning, the toilet will keep refilling, causing constant running.

Turn Off the Water Supply – Locate the shut-off valve near the base of the toilet and turn it clockwise to stop water flow.

Inspect the Flapper – Lift the toilet tank lid and check if the flapper is sealing properly. If it looks worn, cracked, or misshapen, it needs to be replaced.

Replace the Flapper – Remove the old flapper by unhooking it from the flush chain and attaching a new one. Make sure it sits properly over the flush valve opening.

Turn the Water Back On – Flush the toilet and see if the running has stopped.

If it’s too short, it may be preventing the flapper from closing completely. Lengthen it by adjusting the hook or replacing it with a longer chain.

If it’s too long, it may get caught under the flapper, preventing a proper seal. Shorten the chain slightly so there’s only a small amount of slack when the handle is at rest.

Look for Water Flow Issues – If water continues to enter the tank after the flapper has sealed, the fill valve is likely failing.

Adjust the Float – Some toilets use a float ball, while others have a float cup. Adjust the float’s height to ensure the valve shuts off at the correct water level.

Replace the Fill Valve – If adjusting the float doesn’t work, turn off the water supply, drain the tank, and replace the fill valve with a new one. Follow the manufacturer’s instructions for installation.