Toilet Keeps Flushing Non Stop

On this page

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 stop the toilet from flushing. Check the flapper chain for proper tension and ensure the float isn't stuck or damaged. Replace the flapper if it's worn.

Confirm the symptom

Toilet runs continuously after flushing
Water constantly flows into the bowl
Tank refills repeatedly without use
Toilet makes gurgling or running water sounds

Tools and prep

Adjustable wrench
Screwdrivers (flathead and Phillips)
Plumber's putty or silicone sealant
Replacement flapper or fill valve
Turn off water supply to the toilet
Protective gloves and safety glasses

Step-by-step troubleshooting

Turn Off Water Supply
Do: Locate and turn the shut-off valve clockwise to stop water flow.
Observe: Water stops entering the tank.
Means: You can now safely work on the toilet components.
Next: Inspect the flapper and chain
Inspect the Flapper and Chain
Do: Check the flapper for wear or damage and ensure the chain is properly adjusted.
Observe: Flapper closes fully and opens with a flush.
Means: A faulty flapper or chain can cause continuous water flow.
Next: Adjust or replace the flapper
Adjust or Replace the Flapper
Do: If the flapper is damaged, replace it with a new one. Adjust the chain length if necessary.
Observe: Flapper seals properly after flushing.
Means: A properly sealed flapper stops water from flowing into the bowl.
Next: Test the toilet
Test the Toilet
Do: Turn the water supply back on and flush the toilet.
Observe: Toilet fills and stops without continuous running.
Means: The issue is resolved if the toilet functions normally.
Next: Monitor for recurring issues
Check the Float Mechanism
Do: Ensure the float is not stuck or misaligned. Adjust the float height if needed.
Observe: Float moves freely and stops water flow at the correct level.
Means: A misaligned float can cause overfilling and continuous running.
Next: Inspect the fill valve
Inspect the Fill Valve
Do: Check the fill valve for wear or damage. Replace if necessary.
Observe: Fill valve shuts off water properly after the tank fills.
Means: A faulty fill valve can cause continuous water flow.
Next: Final test and monitoring

Common causes

Cause	Likelihood	Difficulty	Part often needed
Faulty Flapper The flapper doesn't seal properly, allowing water to flow into the bowl continuously.	Common	Easy	Toilet flapper
Loose or Broken Chain A chain that's too loose or broken prevents the flapper from closing fully.	Common	Easy	Toilet flapper chain
Stuck or Misaligned Float A float that's stuck or misaligned causes the fill valve to overfill the tank.	Common	Easy–Medium	Float assembly
Worn Fill Valve A faulty fill valve can't shut off water properly, leading to continuous running.	Sometimes	Medium	Fill valve
Cracked Tank or Bowl Cracks in the tank or bowl cause water to leak, triggering continuous refilling.	Rare	Hard	Toilet tank or bowl replacement
Faulty Overflow Tube An improperly positioned overflow tube allows water to continuously flow into the bowl.	Rare	Easy–Medium	Overflow tube adjustment

Parts matching

Replace common parts to fix a continuously running toilet:

Toilet flapper: $5–$15
Toilet flapper chain: $1–$5
Float assembly: $10–$20
Fill valve: $20–$50
Plumber's putty or sealant: $3–$10

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

When to call a professional

Water continues to run after replacing the flapper and adjusting the chain
You notice cracks in the tank or bowl
The fill valve is damaged and you're unsure how to replace it
The problem persists after following all troubleshooting steps

FAQ

How do I know if my toilet flapper is faulty?

If water continuously flows into the bowl after flushing, the flapper may not be sealing properly. Check for wear or damage and replace if necessary.

Can a loose chain cause my toilet to run constantly?

Yes, a loose or broken chain can prevent the flapper from closing fully, causing continuous water flow. Adjust or replace the chain as needed.

What should I do if adjusting the float doesn't stop the toilet from running?

If adjusting the float doesn't resolve the issue, the fill valve may be faulty. Replace the fill valve to stop the continuous water flow.

How much does it cost to fix a continuously running toilet?

Parts typically cost $5–$50, depending on the component. Most repairs can be done in an hour or less with basic tools.