Why is my toilet running constantly after flushing?

A constantly running toilet wastes water and annoys. Fix the flapper, fill valve, or float in minutes.

Category:Plumbing

Difficulty:Easy

Time:15 min

Success:50%

Updated:Jun 10, 2026

quick_referenceQuick Answer

For Why is my toilet running constantly after flushing?, start with "Check the flapper seal": Remove the tank lid. Flush the toilet and watch the flapper. If it doesn't drop fully or hangs up, clean or replace it. Stop DIY if you see water pooling on the floor around the toilet base. 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 Jun 10, 2026. Review the stop conditions before continuing.

account_treeRecovery State

DeviceToilet

Current stateLeak

Specific stateRunning Water

Failed stepFlapper Wear

Likely failure typeWorn Part

DIY boundaryDIY recovery first

paymentsCost decision

help1. Understand the Problem

A toilet that keeps running after flushing usually means the flapper isn't sealing, the fill valve is stuck, or the float is set too high. Water leaks from the tank into the bowl, causing the fill valve to keep running. This is a common, easy DIY fix.

build_circle2. Try This First

Best First Step

Check the flapper seal

Remove the tank lid. Flush the toilet and watch the flapper. If it doesn't drop fully or hangs up, clean or replace it.

visibility3. Visual Guidance

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

Turn off water and flushTurn the shut-off valve clockwise. Flush to drain the tank.

Inspect the flapperCheck for cracks, warping, or mineral buildup. If worn, remove it by unhooking from the pegs.

Install a new flapperHook the new flapper onto the pegs, attach the chain with 1/4 inch slack, and test.

Adjust the floatIf water still runs, bend the float arm down or adjust the float screw so water stops at the fill line.

autorenew4. If That Doesn't Work

Try the next recovery options.

Replace the fill valveIf the flapper is fine, the fill valve may be worn. Replace the entire valve assembly.

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Frequently Asked Questions

Why does my toilet run intermittently?expand_more

A slow leak from a worn flapper causes the tank to lose water, triggering the fill valve. Replace the flapper.

Can a running toilet increase my water bill?expand_more

Yes, a continuously running toilet can waste up to 200 gallons per day, significantly raising your bill.

How do I know if the flapper or fill valve is bad?expand_more

If jiggling the handle stops the running, the flapper is likely bad. If water keeps running after replacing the flapper, the fill valve needs replacement.

What is the average cost to fix a running toilet?expand_more

A flapper costs $5–10; a fill valve costs $15–25. DIY repair is very affordable.