How to Fix a Constantly Running Toilet

A running toilet isn’t just annoying, it can waste hundreds of gallons of water a day and increase your monthly water bill. The good news is that most continuously running toilets can be fixed with simple adjustments or inexpensive parts.

Common Causes of a Running Toilet

1. A Worn or Misaligned Flapper

The flapper is a rubber seal at the bottom of the tank. If it’s warped, dirty, or not sealing properly, water leaks into the bowl, causing the toilet to run nonstop.

2. Faulty Fill Valve

The fill valve controls how much water enters the tank. If it doesn’t shut off correctly, water keeps running and eventually drains into the overflow tube.

3. Incorrect Float Height

The float determines when the fill valve should stop adding water. If it’s set too high, water rises too much and spills into the overflow tube, creating a constant running cycle.

How to Fix a Constantly Running Toilet

1. Check and Clean the Flapper

• Open the toilet tank

• Inspect the flapper for cracks or mineral buildup

• Make sure the chain isn’t too tight or tangled

• If damaged, replace the flapper

2. Adjust the Float

If the water level is too high:

• Find the float adjustment screw or clip

• Lower the float so the water stops about 1 inch below the overflow tube

3. Inspect the Fill Valve

If water continues to flow even after adjusting the float:

• Turn off the water supply

• Remove the fill valve cap

• Rinse the internal parts to remove debris

4. Replace Damaged Parts

If any internal components (flapper, fill valve, float) are too old or worn out, replacing them is the best long-term fix.

When to Call a Plumber

You should get professional help if:

• The toilet still runs after replacing parts

• You notice cracks in the tank

• There’s water leaking from the base or behind the toilet

• The toilet has very old plumbing that needs upgrades

A plumber can diagnose deeper issues and ensure everything is sealed and working correctly.

If you’d rather have a professional handle it, or if the issue keeps returning,

Call Vertical Plumbing at (480) 577-8720