Toilet Running Intermittently/Constantly- How to Fix & Stop

When a toilet runs on its own, it can cost you a lot in terms of the water bills since it means a lot of water is going into the drain without being used to flush the toilet. It can also lead to a phantom flush which is a situation where your toilet flushes itself.

Among the causes of a running toilet include a faulty flapper, faulty fill valve, and the wrong amount of water in the toilet tank. Each of these issues is quite easy to fix. Replacing the flapper, replacing or adjusting the fill valve and adjusting the amount of water on the toilet tank is all you need to fix a running toilet

 As long as you can correctly identify the cause of the problem, you can fix it in a few steps as you’ll learn shortly.

Toilet Running Intermittently NOT Flapper

The two problems that can make a toilet run without involving the flapper are the fill valve and the wrong water level in the toilet tank. The solutions to these issues are as follows:

Wrong water level in the toilet tank

When there’s too much water in the toilet tank, the excess amount will keep overflowing into the overflow tube. This way, it’ll flow into the toilet bowl without necessarily having the toilet flushed. Each time water fills the tank to a level above the overflow tube, the excess amount will flow into the tube and into the ball. This will become a constant issue with water being wasted in the process.

Toilet tank water level

It’s quite easy to establish this issue. Simply open the lid to the toilet tank then check the level of the water in relation to the overflow tube. The overflow tube is a vertical pipe from the base of the toilet tank to just above the water level in the tank. When you open the lid, the top of the overflow tube should be above the level of the water. If the water and the top of the overflow tube are about the same level, it means there’s too much water in the tank.


The solution to this issue is as follows:

First, check the type of float your toilet has

A float mechanism is what determines the amount of water in the toilet tank after each flush. These are mechanisms attached to the fill valve which allow a specific amount of water into the toilet tank.

In this regard, there are two types of float mechanisms one of which is the float ball which attaches to the fill valve with a stem made of metal or plastic.

The float ball goes up and down remaining on the top of the water such that when it reaches a certain level, it closes the fill valve thus keeping the water at this level.

The second type is the float cup which has a small cylinder surrounding the fill valve. This type of float mechanism moves up and down the side of the fill valve regulating the amount of water in the toilet tank.

Fix the float mechanism

The float ball mechanism may have a punctured ball which can be lower than needed thus allowing in more water than is needed. In such a case, replace the float ball altogether. If the stem connecting the float ball to the fill valve is broken or damaged in any way, you should replace it as well.

The float cup mechanism can also get damaged with the cup-like structure getting punctured or damaged in another way. The solution is simply replacing it.

Adjust the level of the float mechanism

The best height for the water in the toilet tank is about 1.5 inches below the top of the overflow tube. To attain that, adjust the water level by adjusting the float ball or float cup as needed.

The float ball can be adjusted downwards either by bending the stem downwards (if it’s made of metal) or turning the screw holding it to the fill valve in a clockwise manner. You might do this several times to get the right water level.

You can adjust the height of the float cup by turning the screw at the top of the fill valve in a clockwise manner until you attain the needed level. With this one as well, you might have to do it several times to attain the level of water needed.

Once you’re done with the procedure above, you can flush the toilet then check if the water is still running into the toilet bowl. If not, it’s fixed. If you still see water running into the toilet and you performed the above procedures well, head over to the next sections since it means the problem isn’t the amount of water in the toilet tank.

Faulty fill valve

The fill valve of your toilet is the part responsible for filling the toilet tank after you flush the toilet. When it’s faulty, water will keep trickling into the toilet bowl even when you’re not flushing it. Also, water can easily overflow in the toilet tank and spill to the floor. Either way, you need to replace this part of the toilet to keep it functioning.

illustration of a toilet fill valve
Fill Valve

The procedure for replacing a toilet fill valve is as follows:

Remove water from the tank

First, shut off the water at the shutoff valve which is located on the wall. The valve should be turned in a clockwise direction until it’s right. Follow this up by flushing the toilet to remove the water from the toilet tank.

The little water remaining at the bottom of the tank should be soaked up using a piece of cloth. You can also simply disconnect the pipe from the wall to the tank then drain any water from the tank. You have to ensure there is no water in the tank before heading over to the next step.

Remove the faulty fill valve

Remove the fill tube from the fill valve as in the previous procedure. Under the toilet tank you will see a lock nut corresponding to the fill valve on the inside of the toilet tank. Holding the top of the fill valve with your hand, you can turn the fill valve lock nut using a wrench by turning it in a counterclockwise direction until it comes loose.

Assuming you haven’t already bought a replacement fill valve for the toilet, you can go to the store with this unit to get a replacement of the exact same size as before. You can also go for a change of the fill valve to one that uses a float cup or float ball as deemed necessary. In our opinion, just replace it with an exact replica.

Install the new fill valve

Position the new fill valve into the part of the toilet tank that the previous fill valve occupied. Insert the lock nut then tighten it in a clockwise direction until it’s tight. Make sure the top part of the fill valve aligns with the inlet into the toilet tank.

After that, insert the fill tube into the water output nozzle located at the top of the fill valve. The fill tube should drain into the overflow tube for the best working of the toilet.

Attach the float mechanism

When the fill valve is securely in place, attach the float mechanism which can either be the float ball or float cup. You then measure the highest point of the float mechanism to be about 1.5 inches below the top of the water surface. This eliminates the issue of having too much water in the toilet tank.

Turn on the water

First, reconnect the pipe from the mains to the toilet tank if you removed it. You should then turn on the water from the mains by turning the shutoff valve counterclockwise until the end of the turn.

You can go ahead testing the toilet by flaying the toilet the checking if any more water is seeping into the toilet tank.

Constant Running Toilet-Flapper Issues and Fixes

The main cause of a constantly running toilet is usually a faulty flapper. The flapper is a piece of rubber or plastic that opens and closes to allow water to leave the tank of toilet or to allow the toilet tank to fill up. The flapper can have various issues including a damaged or stuck chain, a damaged flapper, a dirty flapper or a poorly fixed one.


You can fix flapper issues as follows:

Shut off the water

First, turn off the water at the mains with the shutoff valve. You should turn the valve in a clockwise manner until it feels tight. You then flush the toilet to remove the water in the toilet tank.

Inspect the toilet flapper

The flapper is inside the toilet tank and can only be accessed by removing the lid on the toilet tank. After that, you can check the integrity of the toilet flapper accordingly.

First, you need to check whether the chain holding the flapper is free and working fine. At times, it can get entangled making it shorter than needed. In this shortened state, it will leave the entry to the toilet bowl open and likely to allow water to leak into the boil.

After that, you check the integrity of the toilet flapper. If it has damage of any kind, you should simply buy a new one. If it’s dirty, you should clean it up.

To adjust the chain, remove the chain attached to the flush lever then move it either up or down by a few links then hook it back in. At times, the chain is way too long and it gets under the flapper thus keeping it open and allowing water into the toilet bowl. For this kind of issue, simply clip away the chain with a pair of wire cutters.

If the flapper is dirty from the buildup of dirt or mineral deposits, you can easily clean it up by putting it in a bowl of vinegar for half an hour then giving it a scrub using a soft brush. Rinse it in clean water afterwards. You can also use baby shampoo to clean it.

A worn-out flapper can be replaced in the following way:

  1. Tun off the shutoff valve to stop the water from the mains from flowing into the toilet tank.
  2. Empty the toilet tank first by flushing it and then draining it to make sure there’s no water left in it.
  3. Remove the flapper from the toilet unit.
  4. Prepare the new flapper for installation.
  5. Install the new flapper the same way you removed the old one but now the procedure is in reverse. Make sure the clips go in place and the whole unit fits as needed.
  6. Attach and adjust the flushing chain such that it keeps the flapper closed when not flushing and immediately lifts it up when flushing the toilet.

Turn the water back on then test the integrity of the new flapper. If water still leaks into the toilet bowl, it means you need to adjust it further or it wasn’t the problem in the first place.

Kohler toilet water runs intermittently

When Kohler toilets experience running water intermittently, it’s usually due to a faulty flapper or a broken toilet fill valve. The procedures for replacing the flapper and fill valve on a Kohler toilet are similar to the procedures for the other types of toilets and can thus be borrowed from the procedures above.

American standard toilet intermittent running

Like the other types of toilets, the main causes for an American Standard toilet running intermittently are a faulty flapper and a malfunctioning fill valve. However, this type of toilet has an issue in which the little shafts located on the bottom of the toilet tank can be screwed too far in such that they press the flush button slightly leading to the running water.

The solution to this is simply turning the shafts in a counterclockwise direction until pressure is relieved off the flush button.

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