how to fix a running toilet

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A running toilet can waste hundreds of gallons of water per day while racking up your water bill. This a problem you'll want to address quickly! The best way to fix a running toilet is to start by inspecting the toilet flapper for issues. Toilet flapper issues are one of the most common causes of a running toilet. If the toilet flapper seems fine, try adjusting the water level of your toilet. Finally, if your toilet is still running, you'll probably need to replace the toilet fill valve.

1
Turn off the water and drain the toilet. ^[1] Before you can check the flapper for problems, turn off the water to the toilet. Flush the toilet to drain excess water from the tank. This will allow you to inspect the flapper without having the toilet running constantly.
- The flapper is a round rubber seal that stops water from draining from the tank and into the toilet bowl. When you flush the toilet, the chain pulls the flapper up so fresh water can fill the bowl.
- Problems with the flapper are among the most common causes of a running toilet.
2
Remove the toilet tank lid and look inside. Lay down a towel somewhere safe and out of the way, such as in a corner. Hold either end of the lid firmly with both hands and pull the lid off the toilet. Place the lid on the towel to prevent it from getting scratched.
- Toilet lids are made of heavy ceramic, so don't place them anywhere they can easily be knocked over.
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3
Adjust the chain length if necessary. The chain that pulls the flapper up can cause problems if it's too long or too short. When the chain is too short, it will pull up on the valve when it shouldn't, allowing water to drain constantly. When the chain is too long, it can get caught underneath the flapper and prevent a seal.^[2]
- If there's too much tension on the chain, remove the hook attaching the chain to the flush lever. Move the hook up 1 or 2 links until the chain has more slack. Reattach the hook to the flush lever.
- If the chain is so long that it can get caught under the valve, use a pair of wire cutters to trim a few links from the top of the chain. Reattach the hook to the new top link and reattach it to the flush lever.
4
Inspect the flapper for problems. Remove the flapper by unhooking the sides from the pins at the bottom of the overflow tube, which is the open tube in the center of the tank. Inspect the flapper for mineral deposits, warping, discoloration, disintegration, and other signs of trouble.^[3]
- You can clean a dirty flapper that's got mineral buildup on it.
- A flapper that shows other wear-related problems should be replaced.
5
Clean a dirty flapper. Mineral deposits from the water can build up on the flapper and prevent it from sealing properly, allowing water to run.^[4] To clean the flapper, soak it in a bowl of vinegar for 30 minutes. After 30 minutes, scrub the rubber with an old toothbrush to dislodge buildup and dirt.
- Alternatively, put a few drops of baby shampoo on a rag and use it to wipe down the flapper. This will clean the flapper and add more elasticity to the rubber.
- When the flapper is clean, put it back in place. Attach the hooks on the side to the pins on the overflow tube.
- Turn the water back on and let the toilet tank fill.
- Listen for the sound of water running to see if that fixed the problem.
6
Replace a worn flapper. If the flapper is brittle and hard or doesn't seal well after cleaning it, purchase a new one. Take the worn flapper to the hardware store and purchase a new flapper in the same style and with the same dimensions. You can also buy a universal flapper that will fit any kind of toilet.^[5]
- To attach the new flapper, fit in into place and attach the hooks on the side to the pins on the overflow tube.
- Turn the water back on and test the flapper to see that it's functioning properly, and that the toilet isn't running.
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1
Check the water level. ^[6] When flapper trouble isn't the cause of a running toilet, the next most common cause is the water level. When the water level is too high, water will constantly drain into the overflow tube. Be sure to fix this problem as soon as possible to prevent water from spilling out onto the floor causing major water damage if the toilet gets clogged.
- With the water running and the tank full, look at the overflow tube. This is an open tube in the middle of the tank that connects the tank and the toilet bowl.
- Check to see if water keeps draining into the tube. If that's happening, you can adjust the water level by lowering the float.^[7]
2
Determine the type of float you're dealing with. Water comes into a toilet tank via a fill valve. The fill valve has a float on it that rises or lowers with the water level. The float height is what tells the fill valve to shut off when the tank is full. Therefore, you can lower the water level in the tank by adjusting the height of the float. There are 2 main types of floats:^[8]
- A float ball fill valve will have a long arm attached to the fill valve, and at the end of the arm there will be a rubber ball-shaped float.
- Shake the float ball to determine if there is water inside it. If so, replace it.
- A float cup fill valve will have a small circular cylinder wrapped around the body of the fill valve. The cylinder, or float cup, slides up and down on the fill valve shaft, and its height determines the water level.
3
Lower the float on a float ball fill valve. On top of the fill valve, there will be a screw attaching the float arm to the fill valve. When you turn this screw, you can adjust the height of the float. With a screwdriver, turn the screw a quarter turn counterclockwise to lower the float.^[9]
- Flush the toilet and let the water in the tank refill. Check the water level.
- Ideally, the water level should be 1 to 1.5 inches (2.5 to 3.8 cm) below the top of the overflow tube. Continue adjusting the screw by quarter turns until the water level is right.^[10]
4
Lower the float on a float cup fill valve. The float on a float cup fill valve is adjusted in much the same way. There will be an adjustment screw on the top of the fill valve. When you turn this screw, it will adjust the height of the float. Turn the screw a quarter turn counterclockwise to lower the float.^[11]
- Flush and refill the toilet tank.
- Check the water level.
- Make another quarter-turn adjustment if necessary until the water level in the tank is 1 to 1.5 inches (2.5 to 3.8 cm) below the top of the overflow tube.
5
Check the fill tube if the toilet runs intermittently. The refill tube is a tube attached to the fill valve that fills the tank with water after it's been flushed. This tube should always be above the water line, otherwise it can lead to intermittent running. When the tank is full, make sure the tube isn't in the water.
- To correct a fill tube that dips into the water, simply trim enough of the tube so that it sits above the water line.^[12]
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1
Shut off the water and drain the tank. ^[13] When fixing the flapper and adjusting the water level in the tank doesn't fix a running toilet, it usually means there's a problem with the fill valve. The solution for this is replacing the fill valve. To do this, you must work with an empty tank:^[14]
- Turn off the water to the toilet.
- Flush the toilet.
- Use a sponge to absorb remaining water from the tank. Soak the sponge, wring it out in the sink, and continue until there's no water left in the tank.
2
Disconnect the water supply line. On the outside of the toilet, there will be a water supply line running into the tank. To disconnect this, unscrew the locknut securing the line in place. Turn the screw counterclockwise to loosen it.
- You may need a pair of pliers to loosen the locknut.^[15]
3
Remove the original fill valve. Once the supply line has been disconnected, you'll see a lock nut attaching the fill valve assembly to the toilet on the outside of the tank. Remove this by using an adjustable wrench to turn the lock nut to the left (counterclockwise). Once the lock nut is off, you can pull the old fill valve assembly out from the toilet tank.^[16]
- You may want to take the old assembly to the hardware store when you purchase the replacement. That way, you can be sure to get the right size and style fill valve for your toilet.^[17] Alternatively, you can purchase a universal fill valve.
- You can replace older ball float fill valves with more modern float cup style ones.
4
Install the new fill valve and connect the water. Insert the new fill valve into the same place in the tank. Fit the valve into the hole in the tank where the water supply line comes in. Hook up the water supply line. Tighten the nut in a clockwise direction to tighten it.
- Once the locknut has been hand tightened, use the pliers to turn the nut another quarter turn.
5

Attach the fill tube. Connect the fill tube to the water output nozzle at the top of the fill valve. Position the fill tube so it's draining into the overflow tube. If there's a clip on the overflow tube, attach the fill tube to the clip to keep it in place.^[18]
6

Adjust the float. Check the manufacturer's directions to determine the correct float height for the fill valve you purchased. Use a measuring tape to measure from the bottom of the tank, and adjust the fill valve to the right height by turning the adjustment screw.^[19]
7
Test the fill valve. Turn the water back on and let the toilet tank fill with water. Check the water level, make sure the fill tube isn't in the water, and listen that there isn't any water running. Adjust the float height if necessary. Test the toilet by flushing it and letting it fill up again.
- Once the toilet has been fixed and is no longer running, carefully place the tank lid back on.
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Add New Question

Question

My toilet runs on its own intermittently. I replaced the flapper and the whole tank ball mechanism, but when I flush the toilet, the tank water doesn't fill up to the tank fill line. What should I do?

The next step would be to adjust the float to bring up the water level to the fill line.
Question

Why is there a whistling noise when the toilet is flushed?

Whistling, foghorn, or mechanical noises, etc., are signs of a broken valve. You will need to replace it.
Question

How do I fix a fill valve that is leaking?

The most common leaks are from the bottom of the tank or the bottom of the bowl. For a leak from the bottom of the tank, you may need to replace the tank-to-bowl gasket which can dry-rot with age. Set the tank square on the bowl, and alternate tightening the left and right screws by pushing down on each side that you are tightening. Be careful not to overtighten the bolts, or you may crack the porcelain tank. For a leak from bottom of bowl, replace the wax doughnut with a new one or use a newer composite material. You can find the necessary supplies at a local hardware store.
Question

How do I stop a toilet from hissing when I flush it?

Some fill valves hiss to release pressure. When the hissing is obnoxious or excessive, you can replace the fill valve as newer ones don't hiss as much.
Question

Why is there not enough water in the bowl?

Because there is not enough water in the main tank. Check the water level in the main tank to make sure it is at or close to the fill line, then flush again.
Question

It's leaking from the bottom. What do I do?

There should be a knob you can turn to shut off water going to and from the toilet. (You just can't use the toilet without the water on.)
Question

Why won't the flapper fall back to the closing position after flushing?

The chain may be stuck. Open the lid on the back and see if the chain has a kink in it or is caught on something.
Question

The plumber installed a "new" mechanism that does not have a float. The toilet is now running and not shutting off when the tank refills. What can I do?

The level might be set too high, allowing the water to keep flowing. Check the water level and set it to the fill line. The stopper at the bottom of the tank could also be stuck, or the chain might be caught. Check that the stopper (the rubber piece at the bottom of the tank) completely closes and the chain allows it to close.
Question

How do I stop a leak in my toilet?

If water is leaking from under the toilet onto the floor, the most likely cause is a broken or malfunctioning wax ring. The wax ring seals the connection between the toilet pipes and the sewer pipes. If water is leaking at the base of your toilet, fix the problem by replacing the ring.
Question

Our toilet bowl has a soft rubber gasket that appears to be loose. Can this cause the bowl to not fill properly?

Check to see whether the water leaks out of it. If there is no leakage, it's fine but you might wish to consult a plumber for prevention from future problems.

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If the water doesn't shut off and runs into the overflow tube, either the fill valve or float should be replaced.
If the toilet runs intermittently for short amounts of time, the problem is likely the flapper.
If the water fills up quickly and doesn't shut off right after flushing, the lever chain might be lodged under the flapper.

About This Article

Article SummaryX

One way to fix a running toilet is by adjusting the flapper, which is a rubber seal that stops the water in the tank from draining into the toilet bowl. Start by turning off the water and flushing the toilet to drain the tank. Then, open the tank lid to inspect the handle, chain, and flapper. Make sure the chain is long enough to let the flapper close completely, or move the connection down 1-2 links. If the flapper is cracked, or deteriorating, remove it by unhooking the pins near the overflow tube. Clean the flapper, or purchase a new one to replace it and fix the toilet. To learn how to adjust the water level or fix the fill valve inside your toilet, keep reading the article!

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