Toilet Keeps Filling and Draining

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

Your toilet’s likely having a float or flapper issue. Turn off the water supply, check the float height and flapper seal, and adjust or replace as needed. If the problem persists, replace the fill valve.

Confirm the symptom

Water runs constantly after flushing
Toilet sounds like it's refilling repeatedly
Tank water level is too high or too low
Toilet flushes on its own occasionally

Tools and prep

Adjustable wrench
Screwdrivers (flathead and Phillips)
Bucket or towel
Replacement flapper or fill valve (if needed)
Turn off water supply before starting
Wear rubber gloves to avoid mess

Step-by-step troubleshooting

Turn Off Water Supply
Do: Locate and turn the shut-off valve clockwise to stop water flow to the tank.
Observe: Water stops entering the tank within a few minutes.
Means: You can now safely work inside the tank without overflow.
Next: Drain the tank
Drain the Tank
Do: Flush the toilet to empty the tank. Use a bucket or towel to remove remaining water.
Observe: Tank is mostly empty and no water is running.
Means: You’re ready to inspect internal components.
Next: Inspect the float
Inspect the Float
Do: Check the float ball or cup for damage, and ensure it moves freely without sticking.
Observe: Float is intact and rises with the water level.
Means: Float is functioning; move to the flapper.
Next: Check the flapper
Check the Flapper
Do: Lift the flapper to see if it creates a tight seal when released. Look for warping or wear.
Observe: Flapper doesn’t seal properly or shows damage.
Means: Replace the flapper to stop water from leaking into the bowl.
Next: Adjust or replace the fill valve
Adjust or Replace the Fill Valve
Do: If the float height is incorrect, adjust it. If the fill valve is faulty, replace it with a new one.
Observe: Water level in the tank is about 1 inch below the overflow tube.
Means: The fill valve is working correctly.
Next: Test the toilet
Test the Toilet
Do: Turn the water supply back on and let the tank fill. Flush the toilet and observe for continuous filling.
Observe: Toilet fills once and stops without cycling.
Means: Issue is resolved.
Next: Monitor for a few days

Common causes

Cause	Likelihood	Difficulty	Part often needed
Faulty Flapper The rubber seal wears out or becomes misaligned, allowing water to leak into the bowl.	Common	Easy	Toilet flapper
High Water Level The float is set too high, causing water to spill into the overflow tube and trigger refilling.	Common	Easy	Adjustable float
Stuck Float The float is damaged or clogged, preventing it from rising with the water level.	Sometimes	Easy	Float assembly
Worn Fill Valve The fill valve may be faulty, causing it to cycle water continuously.	Sometimes	Medium	Fill valve
Mineral Buildup Hard water deposits can interfere with the flapper or float mechanism.	Rare	Easy	Vinegar or descaling solution
Chain Tension A chain that’s too tight or too loose can prevent the flapper from sealing properly.	Sometimes	Easy	Adjustable chain
Faulty Toilet Valve A damaged or improperly installed valve can cause continuous water flow.	Rare	Hard	Toilet valve kit

Parts matching

Common parts needed for this repair:

Toilet flapper
Adjustable float
Fill valve
Toilet valve kit
Vinegar or descaling solution
Adjustable chain

Purchase parts that match your toilet model for compatibility.

When to call a professional

Water continues to run after replacing parts
You notice cracks or leaks in the tank or bowl
The toilet is over 25 years old and has multiple issues
You’re unable to locate or access the shut-off valve
The problem recurs frequently despite repairs

FAQ

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

If the water stops when you press the flapper down, the flapper is likely the problem. If the water continues to run even with the flapper closed, the fill valve may be faulty.

Can I use any flapper for my toilet?

It’s best to use a flapper designed for your toilet model. Universal flappers can work but may require adjustments for a proper seal.

Why does my toilet still run after I replaced the flapper?

The fill valve might be faulty, or the water level may still be too high. Check the float height and fill valve function.

Is it normal for a toilet to make noise after flushing?

Some noise is normal, but constant running or refilling is not. This usually indicates a leak or faulty component.

How often should I replace my toilet flapper?

Every 1–2 years, or sooner if you notice leaks or wear. Regular maintenance can prevent water waste and higher bills.