Last Updated on October 1, 2025
A constantly running toilet is usually caused by a worn flapper, a faulty fill valve, or an incorrect water level in the tank. These issues waste water and increase utility bills, but most fixes are quick and inexpensive.
Find out why your toilet keeps running — from worn flappers to faulty fill valves. Learn quick fixes and when to call a plumber.
Common Reasons Your Toilet Keeps Running
1. Worn or Damaged Flapper
The flapper seals water inside the tank. If it’s warped, cracked, or dirty, water leaks into the bowl and the toilet keeps refilling.
2. Faulty Fill Valve
The fill valve regulates water entering the tank. A malfunctioning valve may not shut off properly, causing continuous water flow.
3. Incorrect Water Level
If the float is set too high, water constantly flows into the overflow tube. Adjusting the float often solves this issue.
4. Chain or Handle Problems
A tangled chain or sticky handle can prevent the flapper from closing fully, keeping the water running.
5. Mineral or Sediment Buildup
In hard water areas, buildup inside the tank can stop valves from sealing correctly.
Why It Matters
A running toilet can waste hundreds of litres of water daily, leading to higher water bills and unnecessary strain on your plumbing system.
What To Do Next
- Check the flapper for wear and replace if necessary.
- Adjust the float to set the correct water level.
- Inspect the fill valve and replace if it doesn’t shut off.
- Call a licensed mississauga plumber if the issue persists or you’re unsure.
Final Note
Fixing a running toilet quickly saves water, money, and frustration.
👉 Need fast toilet repairs in Canada? Contact Select Plumbing and Heating for expert service today.
✅ Structured FAQ (Schema-Ready Q&A)
Q1: What is the most common cause of a running toilet?
A worn or misaligned flapper is the most common cause. Replacing it usually solves the problem.
Q2: Can a running toilet increase my water bill?
Yes. A running toilet can waste hundreds of litres daily, significantly raising your water bill.
Q3: How do I know if the fill valve is faulty?
If water keeps entering the tank even after it’s full, the fill valve may be defective and needs replacement.
Q4: Can I fix a running toilet myself?
Simple fixes like replacing a flapper or adjusting the float can be DIY. More complex issues should be handled by a plumber.
Q5: When should I call a plumber for a running toilet?
If replacing the flapper or adjusting the float doesn’t work, or if you notice leaks, it’s best to call a professional.
