Toilet Keeps Making a Flushing Sound

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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

Your toilet may have a faulty flapper or fill valve causing a continuous flushing sound. Turn off the water supply, inspect the flapper for wear or debris, and adjust or replace it if needed. Also, check the fill valve for proper operation and water level.

Confirm the symptom

Toilet sounds like it's running or flushing even when not in use
Water is running continuously into the overflow tube
You hear a hissing or gurgling noise from the tank

Tools and prep

Adjustable wrench
Screwdriver
Bucket or towel
Replacement flapper or fill valve
Turn off water supply to the toilet
Allow the tank to empty completely before starting

Step-by-step troubleshooting

Turn Off Water Supply
Do: Locate the shut-off valve near the base of the toilet and turn it clockwise to shut off the water supply.
Observe: Water stops flowing into the tank.
Means: The tank is isolated from the water supply.
Next: Drain the tank.
Drain the Tank
Do: Flush the toilet to drain as much water as possible. Use a bucket or towel to remove remaining water.
Observe: Tank is mostly empty.
Means: You can now safely inspect internal components.
Next: Inspect the flapper.
Inspect the Flapper
Do: Check the flapper for cracks, warping, or debris. Ensure it sits flat against the flush valve and seals properly.
Observe: Flapper is damaged or doesn't seal tightly.
Means: The flapper is likely causing the leak.
Next: Replace the flapper.
Adjust or Replace the Flapper
Do: If the flapper is damaged, replace it with a new one. If it's just misaligned, adjust the chain length so it allows the flapper to close fully.
Observe: Flapper seals tightly and water stops running.
Means: The leak is resolved.
Next: Test the toilet.
Check the Fill Valve
Do: Inspect the fill valve for proper operation. Ensure the float is set to the correct water level and not stuck.
Observe: Fill valve continues to run or water level is incorrect.
Means: The fill valve may need adjustment or replacement.
Next: Adjust or replace the fill valve.
Test the Toilet
Do: Turn the water supply back on and let the tank fill. Listen for any unusual sounds or continuous running.
Observe: Toilet runs continuously or makes flushing sounds.
Means: Further inspection or repair is needed.
Next: Contact a professional plumber.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Faulty Flapper A worn or damaged flapper doesn't seal properly, allowing water to leak into the bowl and trigger the fill valve.	Common	Easy	Toilet flapper
Misadjusted Chain A chain that's too tight or too loose can prevent the flapper from closing fully, causing a leak.	Common	Easy	None
Faulty Fill Valve A defective fill valve may not shut off properly, causing continuous water flow and a running sound.	Sometimes	Easy–Medium	Fill valve
High Water Level If the water level is too high, it can overflow into the overflow tube, causing a running sound.	Sometimes	Easy	Float adjustment
Clogged Vent Pipe A blocked vent pipe can cause gurgling sounds and improper drainage, mimicking a running toilet.	Rare	Hard	Plumbing vent cleaning
Worn Flapper Seat Mineral buildup or wear on the flapper seat can prevent a proper seal, causing leaks.	Rare	Medium	Flapper seat kit

Parts matching

Common parts needed for a toilet that keeps making a flushing sound:

Toilet flapper
Fill valve
Float adjustment kit
Plunger (for temporary fix)

Purchase parts that match your toilet model for the best fit and performance.

When to call a professional

The toilet continues to run after replacing the flapper and adjusting the fill valve
You hear gurgling sounds from other drains or the main drain
You suspect a clogged vent pipe or main sewer line issue
Water damage is occurring or the toilet is old and needs replacement

FAQ

Why does my toilet sound like it's running but the water level looks normal?

This could be due to a small leak past the flapper or a faulty fill valve. Check the flapper seal and test the fill valve operation.

Can a running toilet increase my water bill?

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

How often should I replace my toilet flapper?

Flappers typically last 1–5 years. Replace it if you notice leaks, wear, or if the toilet runs continuously.

What if adjusting the float doesn't fix the issue?

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