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Why does my toilet keep running after I flush it?

A constantly running toilet wastes water and money. Here's how to diagnose and fix the common causes like a worn flapper or fill valve.

Category:Plumbing
Difficulty:Easy
Time:20 min
Success:50%
Updated:Jul 24, 2026

quick_referenceQuick Answer

For Why does my toilet keep running after I flush it?, start with "Check the flapper seal": Remove the tank lid and flush the toilet. Watch the flapper at the bottom of the tank to see if it settles evenly over the flush valve opening. If it's misaligned or warped, replace it. Stop DIY if you see water pooling around the base of the toilet after flushing. This is listed as a easy recovery and usually takes about 20 min.

verifiedGuide Snapshot

Repair areaPlumbing
Estimated time20 min
DifficultyEasy
Stop conditions3

Last updated Jul 24, 2026. Review the stop conditions before continuing.

account_treeRecovery State

DeviceToilet
Current stateWater Flow
Specific stateRunning Toilet
Failed stepFlapper Wear
Likely failure typeWorn Part
DIY boundaryDIY recovery first
paymentsCost decision

help1. Understand the Problem

A toilet that runs continuously after flushing usually has a problem with the flapper not sealing properly or the fill valve failing to shut off. This is often caused by mineral buildup or a worn rubber part. The fix is typically straightforward and requires no special tools.

build_circle2. Try This First

Best First Step
Check the flapper seal

Check the flapper seal

Remove the tank lid and flush the toilet. Watch the flapper at the bottom of the tank to see if it settles evenly over the flush valve opening. If it's misaligned or warped, replace it.

visibility3. Visual Guidance

See what's happening and how to try the first recovery step.

1
Clean the flush valve seat
Clean the flush valve seatUse a cloth or fine grit sandpaper to gently clean any mineral buildup from the rim where the flapper seals.
2
Adjust the float height
Adjust the float heightLocate the float on the fill valve and turn the adjustment screw or pinch the clip to lower the water level so it stops 1 inch below the overflow tube.
3
Inspect the fill valve for debris
Inspect the fill valve for debrisShut off the water supply and flush to empty the tank. Unscrew the fill valve cap and rinse out any grit or sediment with water.
4
Test the chain length
Test the chain lengthEnsure the flapper chain has about 1/2 inch of slack. If it's too tight, it can lift the flapper slightly, causing a leak.

autorenew4. If That Doesn't Work

Try the next recovery options.

Replace the entire fill valveIf adjusting the float doesn't stop the water, install a new Fluidmaster or similar fill valve assembly.
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Frequently Asked Questions

How much water does a running toilet waste?expand_more
A constantly running toilet can waste up to 200 gallons of water per day, significantly increasing your water bill.
Can I fix a running toilet without turning off the water?expand_more
No, always shut off the water supply valve behind the toilet before opening the tank to prevent flooding.
Why does my toilet run intermittently?expand_more
Intermittent running is usually caused by a slow leak at the flapper seal, allowing water to trickle into the bowl and triggering the fill valve.
What tools do I need for this repair?expand_more
Most toilet repairs only need a pair of pliers, a screwdriver, and possibly a replacement flapper or fill valve kit.

warning5. Stop DIY If

Don't continue if any of these apply.

reportYou see water pooling around the base of the toilet after flushing
reportThe toilet wobbles when you sit on it
reportThe fill valve or tank cracks when you touch it
Still stuck?Get personalized help with AI Recovery.

Same Device Recovery States

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Ghost flushing toiletA toilet that flushes randomly on its own wastes water and drives you nuts. Find the slow leak path and fix it without pulling the entire tank apart.
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Leaking flapperWhen your toilet kicks on for 5 seconds every 20 minutes, water is sneaking past the flapper. Replace it in 10 minutes without touching the tank bolts.
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Slow Filling ToiletYour toilet takes 5 minutes to refill and you hear that sad trickle. It's almost always the fill valve — here's the 10-minute fix.
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Toilet RunningHear water constantly running in the tank? Stop the waste and lower your water bill by fixing the flapper or fill valve.
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Toilet Runs After FlushA constantly running toilet wastes water and money. Learn how to diagnose and fix the flapper, fill valve, or float adjustment.

Similar Failure Pattern

Toilet Runs After FlushIntermittent Toilet Run FixFaucet Handle Base LeakFaucet base leak fix

This page provides general DIY guidance.
If you're unsure, it's always best to consult a professional.