PLUMBING
How to Fix a Running Toilet: 7 Things to Check
A running toilet usually means water is entering the tank continuously or leaking from the tank into the bowl. The sound and water level can help identify which part needs attention.
What to check
1. Watch the tank after a flush
Remove the lid and observe what happens as the tank refills. Continuous incoming water points toward the fill side; water slowly entering the bowl can point toward the flush valve or flapper.
2. Check the flapper or flush valve
Look for a damaged seal, mineral buildup, or a chain that prevents the seal from closing. The seal should settle fully after the flush cycle.
3. Check the tank water level
Use the tank's marked level or the fill-valve instructions. If water rises into the overflow tube, the fill mechanism may need adjustment or replacement.
4. Inspect the fill valve and float
Make sure the float can move freely and is not rubbing against the tank. If the valve keeps admitting water after the tank reaches its normal level, the valve may be worn.
5. Check the handle and chain
A handle that does not return normally or a chain that is too tight can keep the flush mechanism from closing. Confirm that the handle and chain move freely.
6. Look for mineral buildup
Hard-water deposits can interfere with seals and moving parts. Clean or replace components according to their instructions rather than forcing deposits loose.
7. Replace a worn component when needed
Flappers and fill valves are commonly replaceable parts. Match replacement parts to the toilet or existing component and follow the manufacturer's instructions.
How to tell a running toilet from a toilet leak
If the sound is coming from the tank and stops when the water reaches the correct level, focus on the fill mechanism. If water is visibly reaching the floor, treat that as a leak and identify its source before continuing to operate the toilet.
When to call a plumber
Get professional help for a leaking base, cracked porcelain, a shutoff valve that will not operate, repeated failures after replacing common components, or any problem you cannot safely isolate.
Quick checklist
- Watch the tank refill after flushing.
- Check the flapper or flush valve seal.
- Verify the tank water level.
- Inspect the fill valve and float.
- Check the handle and chain.
- Turn off the supply before replacing parts.