Toilet Will Not Stop Running After Flush

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Quick answer
Confirm the symptom
Tools and prep
Step-by-step troubleshooting
Common causes table
Parts matching
When to call a pro
FAQ
Related guides

Quick answer

Turn off the water supply to the toilet. Adjust or replace the flapper valve in the tank. Check the float arm for proper positioning or replace it if damaged.

Confirm the symptom

Water continues to run after flushing
Toilet makes gurgling or hissing sounds
High water bill without increased usage
Tank refills repeatedly without being flushed

Tools and prep

Adjustable wrench
Screwdriver (flathead and Phillips)
Plumber's putty or silicone sealant
Replacement flapper or float
Bucket or towel
Turn off water supply to the toilet
Wear rubber gloves to avoid contact with water and waste

Step-by-step troubleshooting

Inspect the Flapper Valve
Do: Lift the tank lid and check if the flapper is sealing properly after flushing.
Observe: Flapper does not close fully or is damaged.
Means: Flapper is faulty or misaligned.
Next: Replace or adjust the flapper.
Adjust the Float Arm
Do: Check the float arm's position and adjust it so the fill valve shuts off when the tank reaches the correct water level.
Observe: Float is too high or the water level is above the overflow tube.
Means: Float is improperly set.
Next: Lower the float or adjust the water level.
Check the Fill Valve
Do: Inspect the fill valve for debris or mineral buildup.
Observe: Valve is clogged or not closing properly.
Means: Fill valve is faulty.
Next: Clean or replace the fill valve.
Examine the Chain Length
Do: Check the chain connecting the flapper to the flush lever.
Observe: Chain is too long or tangled.
Means: Chain is preventing the flapper from closing.
Next: Adjust or shorten the chain.
Test the Flapper Seat
Do: Inspect the rubber seat where the flapper seals.
Observe: Seat is cracked or worn.
Means: Leakage is occurring due to a faulty seal.
Next: Replace the flapper or seat.
Check for Clogs in the Overflow Tube
Do: Ensure the overflow tube is clear and not obstructed.
Observe: Water is overflowing into the tube or the tube is clogged.
Means: Overflow tube is blocked or misaligned.
Next: Clear the clog or adjust the tube.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Faulty Flapper Valve The flapper does not close properly, allowing water to continuously flow into the bowl.	Common	Easy	Flapper valve
Improper Float Arm Adjustment The float is set too high, causing the fill valve to keep running.	Common	Easy	Float arm
Clogged or Faulty Fill Valve Debris or mineral buildup prevents the fill valve from closing properly.	Sometimes	Medium	Fill valve
Incorrect Chain Length A chain that is too long or tangled prevents the flapper from closing fully.	Sometimes	Easy	Chain
Worn Flapper Seat A damaged or worn rubber seat under the flapper causes leakage.	Sometimes	Medium	Flapper seat
Blocked Overflow Tube Debris or improper alignment in the overflow tube causes continuous water flow.	Rare	Easy	Overflow tube

Parts matching

Common parts needed to fix a running toilet include:

Flapper valve
Float arm or ballcock
Fill valve assembly
Chain or linkage
Plumber's putty or sealant
Overflow tube or repair kit

Purchase parts specific to your toilet model for compatibility.

When to call a professional

The toilet continues to run after replacing all parts
Water is leaking from the base of the toilet
You hear a loud gurgling or hissing sound that persists
The tank does not fill properly despite adjusting all components
You suspect a hidden leak in the plumbing system
You are unsure about the correct part for your toilet model

FAQ

How do I know if the flapper is the problem?

If the flapper does not close fully or is damaged, it will allow water to continuously flow into the bowl, causing the toilet to run.

Can a running toilet increase my water bill?

Yes, a running toilet can waste hundreds of gallons of water daily, significantly increasing your water bill.

How often should I replace the flapper valve?

Flapper valves typically last 1–3 years. Replace them if they become worn or if the toilet starts running.

What if adjusting the float doesn't stop the water?

If adjusting the float doesn't work, the fill valve may be faulty and need replacement.

Can I use any flapper valve for my toilet?

Use a flapper compatible with your toilet model to ensure a proper seal and function.