A toilet that keeps running wastes water and adds to your bill, usually because of a worn flapper, a misadjusted float, or a fill valve problem. This helps you find the cause inside the tank and fix it with inexpensive parts.
What you'll need
- Replacement flapper
- Adjustable pliers or a screwdriver
- Rubber gloves
- A towel
- A bucket
Step by step
- Take off the tank lid and look insideLift the lid straight up and set it somewhere safe. Watch the tank as it refills to see whether water leaks past the flapper or runs into the overflow tube.
- Test the flapper sealPush gently on the flapper when the toilet is running. If the sound stops, the rubber flapper is worn or dirty and is not sealing the flush valve.
- Replace the flapper if neededTurn off the water at the shutoff valve, flush to empty the tank, then unclip the old flapper and attach a matching new one to the same pegs and chain.
- Adjust the chain and floatLeave a little slack in the flapper chain so it closes fully. Lower the float so water stops about an inch below the top of the overflow tube.
- Check the fill valveIf water still runs into the overflow tube after adjusting the float, the fill valve may be faulty and should be replaced with a matching unit.
- Turn the water back on and testOpen the shutoff valve, let the tank refill, and flush a few times. Confirm the water shuts off cleanly and no sound continues.
Handy tips
- Add a few drops of food coloring to the tank; if color seeps into the bowl without flushing, the flapper is leaking.
- Bring the old flapper to the store to match the size and style, since they are not all universal.
- A universal fill valve is inexpensive and usually installs in about fifteen minutes if the flapper is not the culprit.
Heads up
- Turn off the water at the shutoff valve before removing parts to avoid an overflow, and be gentle with the porcelain tank since it can crack.
FAQ
Why does my toilet run intermittently on its own?
A slow leak past the flapper lets the tank level drop until the fill valve briefly turns on. Replacing a worn flapper usually stops these phantom refills.
How much water does a running toilet waste?
A steady leak can waste many gallons a day, which adds up quickly on a water bill, so it is worth fixing soon.
Do I need a plumber for this?
Most running-toilet fixes are simple do-it-yourself jobs with cheap parts. Call a plumber only if the tank or supply line is cracked or leaking outside the tank.