A toilet that keeps running can waste hundreds of gallons of water a day and increase your water bill. While it may sound serious, this problem is usually caused by a small part inside the toilet tank and is often easy to fix.
Understanding why your toilet won’t stop running can help you solve the issue quickly and prevent long-term damage.
Toilet tank with running water caused by faulty flapper or fill valve
What Causes a Toilet to Keep Running?
A running toilet usually means water is constantly flowing from the tank into the bowl. This happens when one or more internal components are not working correctly.
Common Reasons a Toilet Won’t Stop Running
1. Worn or Misaligned Flapper (Most Common)
The flapper seals water inside the tank. If it doesn’t close properly, water leaks into the bowl.
Signs:
- Toilet refills every few minutes
- Water sound never fully stops
Fix:
- Turn off the water
- Remove and replace the flapper
- Make sure it seals flat
2. Fill Valve Set Too High
If the fill valve allows too much water into the tank, excess water flows into the overflow tube.
Fix:
- Adjust the float height
- Ensure water stops below the overflow tube
3. Float Problems
A stuck or damaged float prevents the valve from shutting off.
Fix:
- Make sure the float moves freely
- Replace it if damaged
4. Chain Issues
If the chain connecting the flapper is too tight or tangled, the flapper won’t close fully.
Fix:
- Adjust the chain length
- Ensure slight slack when closed
5. Old or Faulty Fill Valve
Fill valves wear out over time and may not shut off properly.
Fix:
- Replace the fill valve
- This is inexpensive and widely available
Is It Safe to Ignore a Running Toilet?
No.
A running toilet can:
- Waste a large amount of water
- Increase utility bills
- Cause wear on toilet components
Fixing it early saves money and prevents future problems.
When Should You Call a Plumber?
Call a professional if:
- Replacing parts does not fix the issue
- The toilet continues to overflow
- You notice leaks around the base
Final Thoughts
A toilet that keeps running is usually caused by a worn flapper, float issue, or fill valve problem. These fixes are affordable and beginner-friendly, making this one of the easiest plumbing issues to resolve.