Toilet keeps running? How to stop it
A toilet that keeps running or hisses between flushes can waste more water than the rest of the house combined. The cause is almost always one of three parts in the tank.
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Why does my toilet keep running?
A toilet keeps running when water leaks from the tank into the bowl, or the tank overfills into the overflow tube. The usual causes are a worn or warped flapper, a flush chain that is too short or tangled, or a fill valve or float set too high. All three are inexpensive parts, and many homeowners can fix the first two.
- Worn flapper
- Chain too tight or tangled
- Fill valve set too high
- Usually an inexpensive fix
Find the cause
Lift the tank lid
Look at the water level. If it is running into the overflow tube, the fill valve or float is set too high.
Check the chain
There should be a little slack. Too tight holds the flapper open; too loose can tangle under it.
Dye test the flapper
Add food coloring to the tank. Color in the bowl within 15 minutes means the flapper leaks.
Watch it refill
A toilet that refills by itself every so often, called ghost flushing, also points to the flapper.
Common fixes
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Replace the flapper
Flappers harden and warp over time. Match the size, usually 2 or 3 inches.
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Adjust the float
Lower it so water stops about an inch below the top of the overflow tube.
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Replace the fill valve
A fill valve that hisses or will not shut off is worn out and should be replaced.
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Check the flush valve
A cracked overflow tube or worn valve seat means a bigger repair.
When to call
Call a plumber if the parts are replaced and it still runs, the tank or bowl is cracked, water is leaking onto the floor, or the shutoff valve behind the toilet will not turn or drips. Older toilets that use 3.5 gallons or more per flush are often worth replacing with a modern 1.28-gallon model, which also fixes the running for good. See toilet repair for what we handle.
Toilet keeps running: common questions
How much water does a running toilet waste?
A constantly running toilet can waste hundreds of gallons a day, which shows up quickly on your water bill.
Why does my toilet run for a few seconds by itself?
The flapper is leaking slowly, so the tank refills every so often. Replacing the flapper usually fixes it.
Can I fix a running toilet myself?
Often, yes. Flappers and chain adjustments are simple. Fill valves and flush valves take more care.
Should I repair or replace an old toilet?
If it is cracked, uses 3.5 gallons or more per flush, or needs several parts, replacement is often the better value.
Why is water on the floor around my toilet?
That is a different problem: the supply line, the tank bolts or the wax ring. Call us before it damages the floor.
Ready when you are
Tell us what's going on.
A Master Plumber will find the cause, explain it in plain terms, and put your options in writing before any work starts.
- A licensed Master Plumber on every job
- Serving the Upstate since 2010
- Written prices, every job