how to stop running toilet

Why Your Toilet Won’t Stop Running: Troubleshooting & Fixing the Problem

Your toilet won’t stop running, and it’s driving you nuts. You don’t know how to fix the problem, and the idea of calling a plumber is exhausting. This blog post will teach you how to stop a running toilet with step-by-step easy instructions.

Everyone has experienced this problem before, and we can all agree that it’s not fun. But fortunately, there are many things you can do to troubleshoot and fix the problem yourself! The next time your toilet keeps running after flush, be sure to spring into spring cleaning mode with these tricks from our expert plumber.

What Are the Main Reasons Why Toilets Won’t Stop Running? 

There are many reasons why your toilet won’t stop running, and the good news is, these causes are easy to fix. Read on and learn how to stop a toilet from running with our expert advise.

How to Troubleshoot Causes of Toilet Running?

Before going into the solutions, let’s first learn the causes by knowing how to troubleshoot a toilet running.

When your toilet continuously runs, you are practically wasting gallons of water and thereby making your water bill costly. But again, you don’t need to worry since knowing how to stop a running toilet is a fairly straightforward fix.

The three primary common toilet problems why your toilet won’t stop running are a dirty or broken flapper, too short or too long of a chain between the flush valve lever, and lastly, the float or flapper that is not in the correct position.

Turning Off the Water Supply

Before troubleshooting, you should turn off the water supply first, so you don’t get splashed all over and make a mess. 

Just search for the silver knob on the back of your toilet and turn it to the right.

Next, remove the toilet tank lid and begin identifying the toilet parts and how they all work together.

  • The toilet overflow tube dictates where the water level should be in the toilet tank.
  • The float lowers and raises with the water level to signal the pump when to stop.
  • The pump is what refills the toilet cistern after flushing.
  • The rubber flapper prevents the tank water from going into the toilet bowl.
  • The toilet flush valve lever (located outside) is linked to the rubber flapper (found inside the tank)

Causes of a Toilet that Keeps Running after a Flush

#1 Cause of Why Your Toilet Is Running: The Flapper Chain

First of all, be sure the flapper chain is connecting the rubber flapper and flush the lever properly. There are instances when the chain gets disconnected. 

flapper chain

Then, shake the flush valve lever and check if there’s too much or too little slack in the flapper chain. If it is too short, the water will continue to run into your toilet bowl because the flapper is not sealed. 

If the flapper chain is too long, it won’t open the flapper when the toilet flush handle is pushed. If you find it necessary, cut off the excess chain.

Fluidmaster 5104 Universal Kink Free Toilet Flapper Chain Replacement

The chain may also come with a float connected to it. Simply adjust the float so that it sits on top of the water’s surface.

#2 Cause of Why Your Toilet Is Running: Dirty or Leaky Flapper

Gradually, the toilet’s flapper may not seal the drain correctly since it has become broken, warped, or dirty. If you want to replace or clean it, first completely drain the toilet tank and then unhook it from the flapper chain.


Stores should have a variety of replacement options. If it’s possible, match the brand or search for a universal label that looks close to what you have. Once you reattached the flapper, test it with water to check if it seals properly.

how to stop a toilet from running

#3 Cause of Why Your Toilet Is Running: Float Out of Position

The water level inside your toilet’s tank is regulated by an adjustable float. If the adjustable float is positioned too low, it builds a weak flush. If it is set too high, water will spill into the overflow pipe and will continuously run. 

float for toilet

Search for a fill level mark on the inside back of the tank and mark it on the overflow tube so it can easily be seen. If you can’t see any mark, just measure around once-inch down on the overflow tube and create a mark.

Now turn on the water and flush the toilet to check where the water level stops compared to the mark. If the water exceeds the mark, then the float for the pump is a bit high.

Adjust the float down or up accordingly. On some older toilets, you may have to bend the brass rod that is linked to the float.

Newer toilets only need you to slide a clip along a rod or turn a screw. Sometimes, the toilet fill valve that the float links to won’t actually shut off and may be faulty. If this is the case, you might need to purchase a replacement valve.

If your toilet continues to run, we have prepared an in-depth instruction below on how to fix your toilet that won’t stop running.

How to Stop a Running toilet: Step-by-Step Solution to Each Problem 

Before delving into the step-by-step solution to fix your toilet that won’t stop running, make sure you have these tools before starting. If you have a dual flush toilet, don’t worry because you’ll be using the same set of tools.

Also, take note that you might need to replace some components of your toilet, so you better prepare some replacement parts.

Equipment Required to Fix Your Toilet that Won’t Stop Running:

Now, once your tools are all ready, let’s get started.

The first thing you want to do when working out how to stop a running toilet is to turn off your toilet’s water supply. It is usually done by turning off the small knob on the wall to the right of your toilet (toilet water shut off valve).

Simply turn clockwise the knob all the way to the right to close the valve and halt the water supply.

toilet shut off valve

After your stop the water supply, let’s start fixing the first problem of why your toilet keeps running.

Faulty Fill Valve 

A faulty valve leaks too much water into the toilet tank. Sooner or later, the excess water pours down the overflow tube, making an expensive problem. You have some repair options for leaking valves, so replacement is usually the best option.

replacement fill valve

Fill valves have three varieties, but the installation of each is the same.

Older toilets usually come with a ball cock mechanism with a large float and metal lift arm. Another component comes with a smaller float cup that moves up and down the fill tube.

The other style is pressure-sensitive, which is almost flat, and it installs near the toilet tank bottom. The decision is yours on to which kind of valve you want to install.

Here’s how to fix a faulty fill valve:

Step 1: Turn off the Water Supply

Always keep in mind to turn off the water supply of your toilet. Just search for the water valve just below the bottom part of the tank.

Step 2: Push and Hold

Push the flush level down and hold it while the toilet tank is emptying. Holding the flush lever keeps the drain flap open, which enables as much water to exit your toilet tank as possible.

Step 3: Pull Out the Remaining Water

Sponge the remaining water from the toilet tank and wring out the extra into a nearby sink or bucket. For quicker water removal, use a wet and dry vacuum to remove out the remaining water.

Step 4: Loosen the Nut 

Untighten the nut at the bottom of the toilet tank where the water supply line is. This nut is a linkage that links the water supply line to the fill valve. 

Make sure to loosen the nut that holds the fill valve in position. You can use an adjustable wrench to get the nut started, then turn it counterclockwise with your hands to remove it.

Step 5: Remove the Old Fill Valve

Take out the old fill valve by pulling it up and out of the toilet tank. If you want to replace the old device with a cup-style fill valve, measure the height of the overflow tube with a tape measure. 

The tube is in the center of the toilet tank, and the flapper valve connects to it. Unscrew the tower of the cup-style fill valve until it is around one inch taller than the overflow tube height.

Step 6: Insert the Replacement Part

Now, insert the fill valve replacement part into the opening at the bottom of your toilet tank. Secure the waterline and fill valve in position by tightening the nut – a new washer and nut is usually part of the new fill valve kit. Hand-tighten, then provide the nut about ¼ turn with the adjustable wrench. If you overtighten, your porcelain toilet might break.

replace toilet fill valve

Step 7: Insert the Overflow Line

The next step is to insert the overflow line from the fill valve into the overflow tube. The tube comes with a small slot that secures the line in place.

Step 8: Reconnect the Water Supply

Reconnect the water supply, then turn the water supply valve counterclockwise and enable the toilet tank to fill with water.

Step 9: Adjusting Your Toilet Tank’s Water Level

The approach you’ll use for this adjustment will be based on the type of fill valve replacement you pick. For ballcock valves, adjust the metal float arm by unscrewing or screwing it where it links to the fill valve. 

This lengthens or shortens the rod so that the float rides lower or higher. Cup-style floats utilize a spring clip to position the float along with the tower. Pressure-sensitive fill valves come with a small dial you turn right or left to adjust water height. The optimal water level must be around one inch below the top of the overflow tube.

Clogged or Defective Flapper 

Step 1: Turn Off the Water Supply

Again, the first step is to turn off the water supply and drain your toilet tank so you can inspect the flapper without having your toilet running constantly.

Step 2: Take Off the Toilet Tank Lid and Check Inside

Place a towel somewhere safe and out of the way, like in a corner. Hold either end of the toilet lid strongly with your both hands and remove the lid toilet lid. Put the lid on the towel to prevent it from being scratched or damaged.

Step 3: Adjust the Chain Length If Necessary

The chain that pulls the flapper can cause issues if it’s too short or too long. When the flapper chain is too long, it can get caught beneath the flapper and prevent a sealing action. Meanwhile, if the chain is too short, it will pull up on the valve when it must not enable water to drain consistently. 

If there’s excessive tension on the chain, take off the hook linking the chain to the flush lever. Position the hook up one or two links until the chain has more slack. Relink the hook to the flush lever.

On the other hand, if the chain is so long that it can get beneath the valve, you can use a pair of wire cutters to trim a couple of links from the top of the chain. Reconnect the hook to the new top link and reattach it to the flush lever.

Step 4: Inspect the Flapper for Issues

Pull out the flapper by unhooking the sides from the pins beneath the overflow tube. Check the flapper for disintegration, discoloration, warping, mineral deposits, and other signs of trouble.

how do i stop my toilet from running

If there’s only a mineral buildup on the flapper, clean it by simply soaking it in a bowl of vinegar for about 30 minutes. Once 30 minutes is over, scrub the flapper with an old toothbrush to get rid of the accumulated dirt. 

Tip: To prevent mineral buildup, make sure your flapper has proper sealing.

But if the flapper shows wear-related issues, you should replace it entirely. Bring your worn flapper to the nearby hardware store or search online for a new flapper with the exact dimensions and style. 

Tip: You can purchase a universal flapper that will fit to any type of toilet.

Step 5: Turning the Water Supply On

After you’ve cleaned or replaced your flapper, put it back in place. Link the hooks on the side to the pins on the overflow tube. Then turn the water supply back on and allow the toilet tank to fill up.

You can just listen to the sound of water running to check if that solved the issue.

Ballcock or Float Assembly 

A leaking or running toilet can be annoying, but more importantly, it wastes water and can make your water bills expensive! The solution can be as easy as replacing the float device inside your toilet tank.

A float controls the amount of water that fills the tank after flushing. Eventually, the float can become corroded or wear out. There are two most common types of floats: a float valve assembly and a ballcock.

Don’t worry! This is an inexpensive repair task that you can do yourself in less than an hour! First of all, let’s start on how to replace the ball float.

Replacing the Ballcock 

Step 1: Turning Off the Water Supply

Again, the first thing to do is to turn off the water to the water supply line. A shut-off valve usually can be found behind the left side of a toilet. The water supply line may be coming up through the wall or from the floor. 

If you can’t find a shut-off valve at your toilet tank, you should cut off the water supply at the main water line coming into your house. Then flush the toilet in order to empty the tank.

Step 2: Take Out the Old Ballcock

Remove the old connecting float rod and float ball using pliers to unscrew (counterclockwise) the arm from the top of the fill valve.

Step 3: Install the New Ballcock

Fasten the new float ball onto one end of a new linking float rod. Fasten the other end of the rod into the tank’s fill valve.

Step 4: Turn Back On the Water Supply

Turn the water supply on again and let the tank to get filled up with water. Observe the height of the water with the mark on the inside of the toilet tank. Adjust the volume of water by turning the float adjustment screw on top of the fill valve if needed. If you can’t find any adjustment screw, delicately bend the float arm.

Replacing the Float Valve Assembly

Step 1: Turn Off the Water Supply

As usual, the first step is to turn off the water supply. Then flush the toilet to drain the water out of the toilet tank. You can remove the remaining water using a sponge.

Step 2: Uninstall the Assembly

Use an adjustable wrench to untighten the coupling nut at the top of the water supply line found beneath the tank. When it is loose, finish unscrewing it by hand and unfasten the line from the toilet tank.

Step 3: Pulling Out the Old Float Valve Assembly

Put an old towel on the floor below the toilet tank to soak up any water that may gush out from the tank. Unfasten the lock nut that holds the float valve assembly to the tank with the use of an adjustable wrench. Then pull out the old assembly.

how to stop a toilet from running

Step 4: Setting Up the New Fill Valve Assembly

Measure the height of the overflow tube found in the center of the toilet tank. Position the new float valve assembly to the height of the tube. There are many types of assemblies, so make sure to follow the adjustment directions of your unit.

Step 5: Reconnecting the Water Supply Line

Place the float valve assembly through the hole at the bottom of the toilet tank. Then gently push down on the assembly and fasten the provided lock nut onto the shaft beneath the toilet tank. Fasten the lock nut, then turn it one-half turn using a wrench. Reconnect the water supply line to the new assembly using a coupling nut.

Step 6: Connect the New Fill Tube

Attach the new refill tube to the float valve assembly. Fasten the provided angle adapter onto the overflow tube and connect the refill tube to the adapter. If you find any kinks in the fill tube, just cut it to fit.

Step 7: Turn On Back the Water Supply

Turn the water on and inspect the water level. Make necessary adjustments to the float valve assembly depending on the instructions of your assembly model. The water level must be one inch below the top of the overflow tube.

Calling A Plumber Is the Only Option Left

If the simple solutions that we discussed above didn’t work, such as replacing or checking your flapper and ballcock, it might be the best time to call a professional plumber. This is particularly important if the issue is severe.

calling a plumber

Though it can be tempting to perform fixes yourself, you might make the issue worse if you are not confident in your bathroom plumbing skills. A running toilet is quite frustrating, especially because you’re wasting money due wasted water.

However, the impact on your house will be far worse if incorrect repairs cause a full water toilet leak. The worst thing that could happen while you’re fixing the running toilet problem is if you discover there’s a clogged toilet issue. If you want to protect your home from damage, a professional and experienced plumber should be able to help you with all the majority of faults with your toilet quickly.

A plumber can also help you obtain whichever components you need for him to fix the damage. Obviously, you don’t want to get the wrong parts, or you’ll just be wasting money. Hope you can fix your plumbing problems soon!

Last update on 2022-10-30 / Affiliate links / Images from Amazon Product Advertising API