Toilet Not Shutting Off (Troubleshooting Guide)

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 the toilet and check the flapper or fill valve for issues. Adjust or replace these parts to restore normal operation.

Confirm the symptom

Water continues to run after flushing
Toilet tank refills repeatedly without stopping
You hear water trickling into the tank

Tools and prep

Adjustable wrench
Screwdriver
Plumber's putty
Replacement flapper or fill valve
Turn off water supply to the toilet
Wipe up any water spills with a towel

Step-by-step troubleshooting

Turn Off Water Supply
Do: Locate and turn the shut-off valve under the toilet tank 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
Inspect the Flapper
Do: Check the flapper for wear, cracks, or mineral buildup. Ensure it sits properly over the flush valve.
Observe: Flapper is damaged or not sealing correctly.
Means: Replace the flapper to stop the water leak.
Next: Replace flapper
Adjust the Chain
Do: Ensure the chain connecting the flapper to the flush handle is not too tight or too loose.
Observe: Chain is properly adjusted with a slight slack.
Means: The flapper can open and close freely.
Next: Test the flapper
Test the Flapper
Do: Manually lift and release the flapper to see if it seals properly.
Observe: Flapper does not seal or falls too slowly.
Means: Flapper is faulty and needs replacement.
Next: Replace flapper
Check the Fill Valve
Do: Look for a faulty fill valve that may not shut off properly. Check for debris or mineral buildup.
Observe: Fill valve is damaged or clogged.
Means: Replace the fill valve to stop continuous water flow.
Next: Replace fill valve
Adjust the Float
Do: If the float is set too high, it may prevent the fill valve from shutting off. Adjust it to the correct water level.
Observe: Water level is now at the recommended height below the overflow tube.
Means: The fill valve should shut off properly.
Next: Test the toilet

Common causes

Cause	Likelihood	Difficulty	Part often needed
Faulty Flapper The flapper does not seal properly, allowing water to leak into the bowl.	Common	Easy	Toilet flapper
Clogged Fill Valve Mineral deposits or debris prevent the fill valve from closing.	Sometimes	Medium	Fill valve
High Float Setting The float is set too high, causing the fill valve to overfill and not shut off.	Sometimes	Easy	Float adjustment
Worn-Out Fill Valve The fill valve is old or damaged and cannot shut off water flow.	Sometimes	Medium	Fill valve
Damaged Overflow Tube A cracked or damaged overflow tube allows water to continuously flow.	Rare	Medium	Overflow tube replacement
Incorrect Water Level Water level is too high, causing it to spill into the overflow tube.	Sometimes	Easy	Float adjustment

Parts matching

Common parts needed for a toilet not shutting off include:

Toilet flapper
Fill valve
Float adjustment kit
Plumber's putty
Overflow tube replacement

Purchase parts compatible with your toilet model for the best results.

When to call a professional

Water continues to run after replacing parts
You notice significant water damage or leaks
You are unsure about the correct part to replace
The toilet is old and may need a full replacement

FAQ

How do I know if my flapper is faulty?

If water leaks into the bowl after flushing or the flapper doesn't seal properly, it's likely faulty and needs replacement.

Can I fix a running toilet without replacing parts?

Sometimes adjusting the chain length or float setting can resolve the issue without replacing parts.

Why does my toilet keep running even after I replace the flapper?

Another issue such as a faulty fill valve or high float setting may still be causing the problem.

How often should I replace my toilet flapper?

Replace the flapper every 1–2 years to prevent leaks and maintain efficiency.

Is it normal for the toilet to make noise after fixing it?

Some noise is normal as water refills the tank, but constant running or gurgling sounds indicate a problem.