Toilet Keeps Running After Flush? Constant Water Sound in Tank?

Stop a running toilet by replacing the flapper or adjusting the chain and fill valve.

Category:Plumbing

Difficulty:Easy

Time:15 min

Success:50%

Updated:Jul 25, 2026

quick_referenceQuick Answer

For Toilet Keeps Running After Flush? Constant Water Sound in Tank?, start with "Turn off the water supply and remove the tank lid": Locate the shut-off valve behind the toilet (near the wall) and turn it clockwise until it stops. Flush to empty the tank, then lift off the porcelain lid and set it safely aside. Stop DIY if cracked toilet tank. This is listed as a easy recovery and usually takes about 15 min.

verifiedGuide Snapshot

Repair areaPlumbing

Estimated time15 min

DifficultyEasy

Stop conditions3

Last updated Jul 25, 2026. Review the stop conditions before continuing.

account_treeRecovery State

DeviceToilet

Current stateRunning Toilet

Specific stateFlapper Leak

Failed stepFlapper Wear

Likely failure typeWorn Part

DIY boundaryDIY recovery first

paymentsCost decision

help1. Understand the Problem

A toilet that constantly runs usually has a worn flapper that can’t seal the flush valve, or the fill valve isn’t shutting off at the correct water level. The endless water sound not only wastes water but can drive up your utility bill. With a few basic parts, this is a straightforward DIY fix.

build_circle2. Try This First

Best First Step

Turn off the water supply and remove the tank lid

Locate the shut-off valve behind the toilet (near the wall) and turn it clockwise until it stops. Flush to empty the tank, then lift off the porcelain lid and set it safely aside.

visibility3. Visual Guidance

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

Inspect the flapper for damageCheck the rubber flapper at the bottom of the tank. Look for cracks, warping, or a slimy/granular texture. If it’s stiff or misshapen, it won’t create a seal.

Replace the flapperUnhook the old flapper from the overflow tube ears and the chain. Attach a new universal or model-specific flapper, hooking it onto the same pegs and connecting the chain.

Adjust the chain lengthThe chain should have just a little slack—about 1/2 inch when the flush lever is at rest. Too tight holds the flapper open; too loose lets it fall under the flapper. Adjust as needed.

Check and adjust the fill valveIf water still runs, the fill valve float may be set too high. Gently bend the float rod down or screw the adjustment knob so the water level stops 1 inch below the top of the overflow tube.

Turn the water back on and testTurn the shut-off valve counterclockwise, let the tank fill, and flush. Listen for the tank to fill and then stop cleanly. Repeat a couple of times to confirm the fix.

autorenew4. If That Doesn't Work

Try the next recovery options.

Clean the flapper seatSometimes mineral buildup on the flush valve seat prevents a seal. Scrub it with a scouring pad before replacing the flapper.

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Shorten the chainA chain that's too long can get caught under the flapper. Simply unhook it and reattach a few links higher to eliminate slack.

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Frequently Asked Questions

Why does my toilet keep running every few minutes?expand_more

A silent but intermittent run (a ‘ghost flush’) means water is slowly leaking from the tank into the bowl through the flapper. Replace the flapper to stop it.

Can I adjust the flapper chain?expand_more

Yes. The chain should have a little slack but not so much it gets trapped. You can move the hook to a different link to fine-tune.

What if replacing the flapper doesn’t stop the running?expand_more

Then the flush valve seat may be pitted or the fill valve is failing. You can resurface the seat with a repair kit or replace the fill valve assembly.

Is it safe to use bleach toilet tablets?expand_more

Long-term use of in-tank bleach tablets can degrade rubber flappers and seals, causing leaks. It’s better to clean the bowl manually.