Why Does Toilet Water Keep Running? 6 Ways to Fix It Fast

Toilet water that continues to run is not only an annoyance but also a serious waste of water. This issue can cause your water bills to skyrocket and, in some cases, cause unnecessary wear and tear on your plumbing system.

Let’s explore the common reasons why your toilet keeps running and how to resolve each one quickly.

Why Does Toilet Water Keep Running?

A continuously running toilet usually indicates an issue within the tank, such as a worn-out flapper, an improperly adjusted float, or a malfunctioning fill valve. Identifying the root cause can help you fix the problem efficiently, saving water and preventing higher utility bills.

Common Causes of a Constantly Running Toilet Water

There are several reasons why your toilet water might continuously run. Understanding the root cause is the first step in finding an effective solution. Here are the most common culprits:

1. Faulty Flapper: A worn-out or improperly sealing flapper can let water leak from the tank into the bowl.
2. Improper Chain Length: If the chain attached to the flapper is too short or too long, it may prevent the flapper from sealing correctly.
3. Adjustable Float Set Too High: An improperly placed float can cause water to rise and spill into the overflow tube and continuously run.
4. Malfunctioning Fill Valve: A faulty fill valve can lead to water constantly flowing into the tank without stopping.
5. Sediment Buildup: Over time, minerals from hard water can build up inside the tank, disrupting the proper functioning of the toilet components.
6. Cracked Overflow Tube: A damaged or cracked overflow tube may cause water to continuously drain into the toilet bowl.

How to Fix Toilet Water Keeps Running

Fixing a running toilet is usually straightforward and can be done with a few basic tools. Follow these steps to diagnose and resolve common issues like a faulty flapper, incorrect water level, or malfunctioning fill valve.

Step 1: Check and Replace the Flapper if Necessary

The flapper, a rubber valve at the bottom of the toilet tank, is the most common culprit when it comes to a running toilet. It regulates the flow of water from the tank into the toilet bowl during a flush. If the flapper is damaged, worn out, or not sealing correctly, it will allow water to leak into the bowl, causing the toilet to run constantly.

How to Fix a Faulty Flapper:

1. Turn off the water supply to the toilet. You can usually find the shut-off valve behind the toilet near the floor.
2. Remove the tank lid and inspect the flapper. If it appears cracked, warped, or covered in mineral deposits, it’s time to replace it.
3. Clean the flapper if it’s dirty. Sometimes a build-up of debris can prevent the flapper from sealing tightly.
4. Replace the flapper if necessary. Make sure to buy one that matches your toilet’s model and ensure it fits properly.
5. Reconnect the chain and adjust its length to ensure it doesn’t hang too tightly or loosely, which can affect the flapper’s ability to seal.
6. Test the flush to confirm the fix. If the toilet no longer runs, you’ve successfully solved the problem.

Step 2: Adjust the Length of the Flapper Chain

Another common issue that causes a toilet to run is an improperly sized chain attached to the flapper. If the chain from the flush lever to the flapper is too long, it can get caught under the flapper, preventing it from sealing. If it’s too short, it might not allow the flapper to close fully.

How to Adjust the Chain:

1. Examine the chain to see if there is too much slack. If the chain is too long, it can interfere with the flapper’s ability to close properly.
2. Adjust the length by either shortening or lengthening the chain. Ideally, you want about half an inch of slack when the flapper is closed.
3. Test the flush to make sure the flapper opens and closes correctly. This should prevent the toilet from running.

Step 3: Adjust the Float in the Tank

If the water level in the tank is set too high, it will overflow into the overflow tube, keeping the toilet running. This is a common issue, particularly if the float inside the tank is not adjusted properly.

How to Adjust the Water Level:

1. Locate the float inside the tank. Depending on the type of float (ball float or cylinder float), the adjustment process will vary.
2. If you have a ball float: Gently bend the arm downward to lower the water level. Be careful not to break it.
3. If you have a cylinder float: Locate the adjustment screw on the fill valve. Turn the screw to raise or lower the float, adjusting the water level accordingly.
4. Flush the toilet and check if the water stops running once the tank fills up. The water level should be about an inch below the top of the overflow tube.

Step 4: Inspect and Clean the Fill Valve

A faulty or clogged fill valve can also cause a toilet to run continuously. The fill valve is responsible for refilling the tank after a flush, and if it’s not functioning correctly, water may keep running into the tank.

How to Fix a Malfunctioning Fill Valve:

1. Turn off the water supply and flush the toilet to empty the tank.
2. Remove the fill valve cap and check for any debris or mineral build-up. Hard water can cause sediment to accumulate, which can prevent the valve from closing properly.
3. Clean the fill valve with vinegar and water to remove any mineral deposits.
4. If the valve is still not functioning properly, replace it with a new fill valve.
5. Reattach the cap, turn on the water supply, and test the toilet to ensure it no longer runs continuously.

Step 5: Remove Sediment Buildup

Over time, mineral deposits from hard water can accumulate in various parts of the toilet, such as the fill valve or flapper. This can interfere with the proper function of these components, causing the toilet to run constantly.

How to Remove Sediment Buildup:

1. Turn off the water supply and flush the toilet to drain the tank.
2. Remove any parts that are covered in sediment, such as the flapper or fill valve.
3. Soak the parts in vinegar for several hours to dissolve the mineral deposits.
4. Use a soft brush to scrub off any remaining deposits.
5. Reinstall the parts and test the toilet to ensure everything is working properly.

Step 6: Replace a Cracked Overflow Tube

A cracked or damaged overflow tube can also cause a toilet to run. If the overflow tube is cracked, water will continuously drain from the tank into the toilet bowl.

How to Replace a Cracked Overflow Tube:

1. Turn off the water supply and flush the toilet to empty the tank.
2. Remove the old overflow tube by disconnecting it from the fill valve and the tank wall.
3. Install a new overflow tube, ensuring it fits securely into place.
4. Reconnect the fill valve and any other parts that were disconnected.
5. Test the flush to make sure the water no longer runs continuously.

How To Prevent Future Toilet Running Issues

Once you’ve repaired the toilet, there are several steps you can take to prevent the issue from recurring. Proper maintenance and care will help ensure the longevity of your toilet and save you money on your water bill.

Tips for Preventing Toilet Running:

• Regular Maintenance: Periodically check the flapper, fill valve, chain, and overflow tube for wear and tear. This can help catch issues before they cause problems.
• Use High-Quality Parts: When replacing any components, choose high-quality parts that will last longer and function better.
• Monitor Water Pressure: High water pressure can cause strain on your toilet’s internal components. Consider installing a pressure regulator if your water pressure is too high.
• Avoid Harsh Chemicals: Chemical toilet cleaners can damage the rubber components inside the tank. Use gentle cleaners to preserve the integrity of the parts.

When to Call a Plumber

If you’ve tried all of these fixes and your toilet is still running, it may be time to call a professional plumber. There could be a more serious issue, such as a crack in the toilet base, a broken mechanism, or a hidden leak. A plumber will have the experience and tools to diagnose and resolve more complex plumbing issues such as replacing the toilet.

Final Thoughts on Fixing a Running Toilet

A constantly running toilet is more than just a minor inconvenience—it can waste hundreds of gallons of water and increase your utility bills. Fortunately, most causes of a running toilet can be fixed quickly and easily with a few simple tools and parts.

By following the detailed steps in this guide, you can save both water and money while preventing future issues. However, if the problem persists, don’t hesitate to call a professional plumber for help.

1. What is the most common cause of a constantly running toilet?

The most common cause of a constantly running toilet is a faulty flapper. If the rubber flapper at the bottom of the tank is worn, cracked, or not sealing properly, it allows water to continuously leak into the bowl, causing the toilet to run.

2. Does toilet water increase water bill?

Yes, a running toilet can significantly increase your water bill. Even small leaks from a faulty flapper or fill valve can waste tens of gallons of water per day, resulting in higher utility costs.

3. How do I know if my flapper or flush valve is bad?

You can tell if the flapper is bad if it fails to create a tight seal, leading to water continuously leaking into the bowl. If the flush valve is cracked or corroded, it can also cause similar issues, with water constantly refilling or draining from the tank.

Check out our next article: Toilet Tank Losing Water But No Leak: Causes and Solutions

Paul Wilson( Licensed Plumber )

Paul Wilson is a highly skilled plumber with over ten years of experience in the industry. He holds an IDPH license and takes pride in his ability to tackle many plumbing issues and successfully complete even the most challenging projects.