Runs constantly after flush
Check whether water is flowing into the overflow tube. If yes, adjust the float or inspect the fill valve.
How to Fix a Running Toilet
A running toilet is usually a tank problem: the flapper is leaking, the chain is holding it open, the float is too high, or the fill valve is not shutting off.
Running Toilet Symptoms
Refills every few minutes
A slow tank-to-bowl leak usually points to a flapper that no longer seals cleanly.
Stops when flapper is pressed
Replace the flapper or clean the valve seat before replacing more expensive parts.
Quick Diagnosis
- Water entering overflow tube means float or fill valve
- Running stops when flapper is pressed means flapper or valve seat
- Tight or tangled chain can hold the flapper open
- Random refills usually mean a slow tank-to-bowl leak
- Hissing often points to fill valve debris or wear
Safety Checks
- Find the shutoff valve before removing parts
- Do not overtighten plastic or porcelain parts
- Use towels and a bucket if disconnecting the supply line
- Stop if the shutoff valve leaks or will not close
- Call a plumber for floor leaks or cracked porcelain
Common Questions
Why does my toilet keep running?
The most common causes are a worn flapper, chain tension, float height, or a fill valve that will not shut off.
What is the fastest running toilet test?
Remove the lid and press down on the flapper. If the running stops, the flapper or valve seat is likely leaking.
When should I call a plumber?
Call a plumber if water is leaking onto the floor, the shutoff valve will not close, porcelain is cracked, or a supply connection leaks.
Related Running Toilet Resources
Plan This Project in ChatDIY
Use ChatDIY to diagnose what you see inside the tank, including photos, water level, chain slack, flapper condition, and fill valve behavior.