A running toilet isn’t just annoying — it can also waste a significant amount of water and increase your utility bill. Knowing how to fix a running toilet yourself can save you both money and frustration. 

    Fortunately, most running toilet issues can be easily resolved by identifying and fixing the root cause of the problem. 

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    Problems With a Constantly Running Toilet

    A constantly running toilet can cause a variety of problems that may affect your home, wallet, and the environment. Here are some of the most common problems associated with a constantly running toilet:

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    • Increased water bills: A running toilet can waste a significant amount of water, which can result in higher water bills. In some cases, a constantly running toilet can waste hundreds of gallons of water per day, depending on the severity of the issue.
    • Wasted water: A constantly running toilet wastes a significant amount of water, which can put unnecessary strain on your local water supply. This can cause a shortage of water in your community, especially during periods of drought.
    • Water damage: If the water level in the tank is too high, it can overflow and cause water damage to the surrounding area. This can lead to mold growth, damage to flooring or walls, and other costly repairs.
    • Damaged components: The constant running of water can damage components of the toilet such as the flapper valve or fill valve. This can result in the need for repairs or replacements, which can be costly.
    • Environmental impact: A constantly running toilet can have a negative impact on the environment by wasting water and increasing your carbon footprint. Water treatment facilities consume large amounts of energy, and the energy used to treat and pump water is a significant contributor to greenhouse gas emissions.

    In summary, a constantly running toilet can cause a variety of problems that can affect your finances, your home, and the environment. It’s important to address any running issues promptly to prevent further damage and waste.


    Parts of the Toilet

    Homeowners with older houses often ask how they can stop a constantly running toilet. There are a couple of simple causes with equally simple fixes. But first, you need to understand the inner workings of your porcelain throne. 

    There are three main components that can cause a running issue: the flapper, the float, and the fill valve.

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    Let’s start with the flapper. This little rubber seal covers the flush valve at the bottom of the tank. When you flush the toilet, the flapper lifts up to allow water to flow from the tank into the bowl. 

    If the flapper is worn or damaged, it won’t seal properly, causing water to constantly leak from the tank into the bowl. This triggers the fill valve to keep running to refill the tank, therefore leading to a continuous flow of water and a headache for you.

    Next is the float. This buoyant object sits on top of the water in the tank. When the tank is full, the float rises and triggers the fill valve to shut off, stopping the flow of water into the tank.

    If the float isn’t properly adjusted or becomes damaged, it may not be able to signal the fill valve to shut off, consequently causing the tank to overfill and the fill valve to constantly run. Not ideal, to say the least.

    Last but not least, we have the fill valve. This is responsible for regulating the flow of water into the tank. If the fill valve is damaged or worn, it won’t be able to properly control the water flow, leading to a constantly running toilet.


    Identify the Cause of the Problem

    Now that you know the parts of your toilet, how can you diagnose the issue? Start by listening for the sound of running water and visually inspecting the toilet for leaks. 

    First, check for leaks in the toilet. Even a small leak in your toilet can cause it to constantly run.

    Check the base of the toilet, the water supply line, and the tank for any signs of water. If you notice a leak, you may need to tighten a connection or replace a seal.

    Then check the water level in the tank to see if it’s too high or too low. Try adjusting the float to see if that resolves the issue. 

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    If the flapper is not sealing properly, it could be due to a buildup of mineral deposits on the valve seat. Try cleaning the valve seat with a cloth or gentle abrasive cleaner to improve the seal.

    If these steps don’t work, you may need to replace the flapper or fill valve to fully fix the problem.


    Adjust the Float

    A faulty float can fail to signal the fill valve to shut off when the tank is full. This can lead to an overfilling of the tank, which then triggers the fill valve to continuously run. This causes a constant flow of water into the tank and ultimately, into the bowl.

    Adjusting or replacing a float on a toilet is a relatively simple task that can fix a toilet from constantly running.

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    Here are the basic steps:

    1. Turn off the water supply: Locate the shut-off valve behind the toilet and turn it clockwise to shut off the water supply.
    2. Remove the tank lid: Lift the tank lid off the tank and set it aside.
    3. Locate the float: The float is a buoyant device that rises and falls with the water level. It’s usually attached to the fill valve by a metal or plastic arm.
    4. Adjust the float: To adjust the float, gently bend the metal or plastic arm up or down to raise or lower the float. If the water level in the tank is too high, bend the arm downward to lower the float. If the water level is too low, bend the arm upward to raise the float.
    5. Test the toilet: Flush the toilet and let it fill. The water level in the tank should stop just below the top of the overflow tube. If it doesn’t, adjust the float again until the water level is correct.
    6. Turn the water supply back on: Turn the shut-off valve counterclockwise to restore the water supply.

    Adjusting the float on a running toilet is a simple fix that can save you money on your water bill and prevent water waste. If you’re unsure about adjusting the float yourself, consult a professional plumber.


    Replace a Running Toilet’s Tank Flapper

    The flapper valve is a rubber seal at the bottom of the tank that opens and closes to let water in and out.If the rubber flapper at the bottom of the toilet tank is warped or damaged, water will seep out around it, causing the toilet to continue to run.

    Here’s how to replace a defective flapper, and ultimately, fix a running toilet.

    • Turn off the water supply: Locate the shut-off valve near the base of the toilet and turn it clockwise to shut off the water supply.
    • Drain the tank: Flush the toilet to drain as much water as possible from the tank. Use a sponge or towel to remove any remaining water.
    • Remove the old flapper: Unhook the chain connecting the flapper to the flush lever. Remove the old flapper from the flush valve at the bottom of the tank. Take note of the shape and size of the flapper so you can purchase the correct replacement.
    • Install the new flapper: Install the new flapper in the flush valve by aligning it with the opening and securing it in place. Reconnect the chain to the flush lever, making sure there is a slight amount of slack in the chain.
    • Turn the water supply back on: Turn the shut-off valve counterclockwise to turn the water supply back on, then allow the tank to fill. Be sure to check for any leaks.
    • Test the flush: Flush the toilet a few times to ensure the flapper is working properly and creating a proper seal.
    Today’s Homeowner Tips

    There are many products out there that make flapper replacement easy. For instance, Fluidmaster’s 502 PerforMAX Water-Saving, Adjustable Flapper offers a customized flush. To use it, you just have to turn the dial left for more water per flush, or right for less, depending on your needs.

    Replacing a running toilet’s tank flapper is a simple and inexpensive fix that can save you money on your water bill and prevent water waste. If you’re unsure about replacing the flapper yourself, consult a professional plumber.

    Watch: How to Replace a Toilet Flapper Valve


    Adjust the Fill Valve

    The fill valve is the mechanism that refills the tank after a flush. If water is constantly running into the overflow tube in the toilet tank, the fill valve in the tank needs to be adjusted.

    Here’s how to adjust the water level in the tank, and ultimately, fix a running toilet:

    • Turn off the water supply: Locate the shut-off valve behind the toilet and turn it clockwise to shut off the water supply.
    • Remove the tank lid: Lift the tank lid off the tank and set it aside.
    • Check the water level: The water level in the tank should be about one inch below the top of the overflow tube. If it’s higher than that, the fill valve may be improperly adjusted.
    • Locate the adjustment screw: The adjustment screw is usually located on top of the fill valve. It’s a small screw that can be turned with a flathead screwdriver.
    • Adjust the fill valve: To lower the water level, turn the adjustment screw counterclockwise.* To raise the water level, turn the screw clockwise. Turn the screw a quarter turn at a time and check the water level each time until it’s at the correct level.
    • Test the toilet: Flush the toilet and let it fill. The water level in the tank should stop just below the top of the overflow tube. If it doesn’t, adjust the fill valve again until the water level is correct.
    • Turn the water supply back on: Turn the shut-off valve counterclockwise to restore the water supply.

    *Note: Some tanks have other methods of adjusting the height of the float.

    Diagnosing a Faulty Fill Valve

    If the fill valve is worn or faulty, it may not be able to properly regulate the flow of water, which can cause a running toilet.

    To diagnose a faulty fill valve, you can start by checking the water level in the tank to see if it’s too high or too low. You can also listen for running water to see if the fill valve is constantly running. If you suspect a problem with the fill valve, you may need to replace it to fully resolve the issue.

    Replacing a fill valve is a bit more involved than adjusting a float or replacing a flapper, but it’s still a task that can be done with basic tools and some patience. If you’re not comfortable doing this yourself, contact a professional plumber to ensure the job is done correctly.


    Additional Tips

    Preventing a running toilet can save you from the inconvenience and expense of repairs. Here are some tips to help you prevent a running toilet:

    1. Regular maintenance: Conduct regular maintenance checks on your toilet to ensure it’s functioning correctly. Check for leaks, test the flushing mechanism, and clean the tank and bowl regularly.
    2. Avoid flushing non-flushable items: Avoid flushing anything down the toilet that isn’t designed to be flushed, such as feminine hygiene products, paper towels, or wet wipes. These items can clog the toilet and cause damage to the flushing mechanism.
    3. Avoid using chemical cleaners: Chemical cleaners can be harsh on your toilet’s components and cause damage over time. Instead, use a non-toxic cleaner or natural alternatives like vinegar and baking soda to clean your toilet.
    4. Replace old components: If your toilet is old or the components are worn, consider replacing them before they start causing problems. It’s better to replace them preventatively than wait for them to fail.
    5. Educate family members: Make sure everyone in your household knows how to use the toilet properly and understands what shouldn’t be flushed down it. This can prevent clogs and damage to the toilet’s components.
    Today’s Homeowner Tips

    If you really want to save money on your water bill you should probably consider replacing that old toilet with a new one. Some older toilets use as much as 3½ gallons of water per flush. Nowadays, the law requires newer models to operate with a maximum of 1.6 gallons.

    Watch the video at the beginning of the article to learn more. Or, click on your state below to find local plumbing experts:

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    Further Reading

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    Danny Lipford

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    Danny Lipford is a home improvement expert and television personality who started his remodeling business, Lipford Construction, at the age of 21 in Mobile, Alabama. He gained national recognition as the host of the nationally syndicated television show, Today's Homeowner with Danny Lipford, which started as a small cable show in Mobile. Danny's expertise in home improvement has also led him to be a contributor to popular magazines and websites and the go-to source for advice on everything related to the home. He has made over 200 national television appearances and served as the home improvement expert for CBS's The Early Show and The Weather Channel for over a decade. Danny is also the founder of 3 Echoes Content Studio, TodaysHomeowner.com, and Checking In With Chelsea, a décor and lifestyle blog.

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