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Why Does My Toilet Keep Running?

We’re all pretty familiar with that not-so-soothing sound of the water in the toilet constantly running - alongside the concern that comes with it! 

Nobody likes suspicious sounds coming from their household essentials, but don’t worry just yet. We’re here to ease your mind with some potential reasons that your toilet keeps running, and the next steps to take. Without further ado, let’s figure out how to stop a toilet from running together!


Causes Of A Running Toilet

Toilet Flapper

Sure, the phrase “check your toilet flapper” isn’t necessarily an invitation to the thrill-seeking event of the year, but it might just help you stop that pesky toilet constantly running. The purpose of a toilet flapper is to seal the water in the tank, so if this has cracked or decayed slightly then it’s probably not on top form. 

In layman’s terms, you flush the toilet, a chain pulls the toilet flapper up to let water flow into the toilet bowl, and then once the tank has expelled enough water, the flapper returns to its original position and re-seals the tank. Naturally, if the flapper is cracked, it can’t seal the tank properly which allows water to escape and creates that lovely running sound you’re currently enjoying.


So how do we fix it? Here’s a few simple steps to check if your flapper is causing the issue, and where to go from there:

Step 1
Turn off your water and drain the toilet so you’re able to check the flapper without the toilet water constantly running.

Step 2
Take the lid of your toilet tank off and take a peek inside by carefully lifting it with both hands. Be sure to place the lid somewhere safe as these are generally made of ceramic and don’t take kindly to falling from precarious temporary storage locations.

Step 3
Check the length of the chain attached to your flapper. If it’s too long / short this could prevent the flapper from returning to the correct position, meaning your toilet tank isn’t effectively sealed. Adjust the chain to the correct length if this is the case.

Step 4
Have a closer look at the flapper for any problems. A flapper with build up of dirty residue may not be functioning well and simply need a clean; however, a flapper with cracks or signs of being worn will likely need replacing. 

To clean a dirty flapper, place it in a bowl of vinegar for around 30 minutes and scrub any remaining muck off with a toothbrush afterwards.

Step 5
If adjusting the chain length and cleaning the flapper doesn’t work, you most likely need a new flapper, so take the old one along to your local hardware store and get your hands on a near identical model. Universal flappers are also pretty common so you won’t struggle to find a match luckily!

Fit your new toilet flapper into place and attach the hooks on the side to the overflow tube.

Finally, turn your water back on and check that your toilet has stopped running.


Incorrect Water Level

If your toilet water level is too high, any residual water will constantly drain into the overflow tube causing that unpleasant running water sound. It’s important that you get this issue resolved as quickly as possible to prevent any water damage to your bathroom.

To check if the problem is your water level, look for an open tube in the middle of the tank that connects the tank and toilet bowl - that’s your overflow tube. Check whether water keeps draining into the overflow tube. If that’s the case, then it’s likely the reason your toilet keeps running and you’ll need to adjust the water level by lowering the float. Here’s how:


Step 1
First, figure out the type of float you’re dealing with. Water enters the toilet tank via a fill valve which has a float that rises and falls with the water level. The float height tells the fill valve when the tank is full in order to shut it.

You can lower the water level in your tank by adjusting the height of the float, of which there are two main types:

A float ball fill valve has a long rubber arm attached to the fill valve and a rubber ball-shaped float.

A float cup fill valve has a small cylinder wrapped around the fill valve. The cylinder (float cup) slides up and down the valve shaft and determines the water level via its height.

Step 2
Once you’ve figured out what kind of fill valve you have, the next step in learning how to stop a toilet from running is lowering the float.

To do so on a float ball fill valve, there will be a screw on top of the valve for adjustments. Use a screwdriver to turn this a quarter turn counterclockwise in order to lower the float. 

For a float cup fill valve, do the same as above and turn the screw a quarter turn counterclockwise to reduce the height of the float. 

After completing the above, flush and refill the toilet tank. Check the water level; an ideal height for your water level is 1 to 1.5 inches below the top of the overflow tube. If it’s still not quite right, try another quarter turn counterclockwise.

Step 3
If the toilet water is running intermittently, have a look at the fill tube. This is a tube attached to the fill valve that fills your toilet tank with water after flushing. This should always be above the water line to prevent intermittent running. Check this is above the water level when the tank is full, and if not then be sure to trim the tube so it does sit above the water line. 


Check The Float

An incorrectly adjusted or faulty float can disrupt the effectiveness of your toilet tank and likely mean that the toilet keeps running. 

Lift the lid of your tank and check the float hasn’t become tangled with the chain as this will affect the functionality of your float. If everything’s fine in that department, then it could be an issue with the float itself. 

Shake the float itself and listen for any water moving around inside. If you hear water sloshing it’s likely that the float is clogged up with water and will need replacing entirely.

Pop into your local hardware store or order a new float online and things should be right as rain in no time. Once you’ve replaced the float, ensure this has fixed the problem by test flushing your toilet before use.



Faulty Fill Valve

A faulty fill valve can often be the root of the problem when your toilet keeps running. If none of the above have helped, then you’ll probably need to replace your fill valve - here’s how to do just that:

Step 1
Shut off your water and drain your tank fully, using a sponge to soak up any excess water remaining at the bottom of the tank.

Step 2
Disconnect the water supply to your toilet by unscrewing the lock nut securing your water supply line into place.

Step 3
Remove the old fill valve. After disconnecting the supply line, you’ll come across a lock nut attaching the fill valve to the toilet on the outside of the tank. Remove this by using an adjustable wrench and turning the lock nut counterclockwise.

Once you’ve removed the lock nut, you’ll be able to pull the old fill valve assembly out from the toilet tank. Take this with you to the hardware store so they can help you find the best fit.

Step 4
Install the new fill valve and connect the water.  Pop your new fill valve into the same place you removed the old one, connect the water supply line, and tighten the nut clockwise until secure. Then, connect the fill tube to the water output nozzle at the top of the fill valve. Position this so it’s draining over the overflow tube, using a clip to secure it in place if provided.

Step 5
Adjust the float, following the manufacturer’s directions to determine the correct height for the fill valve you have. Achieve the desired fill valve height by turning the adjustment screw.

Step 6
Test your fill valve. Ensure you no longer face the ‘toilet keeps running’ issue by turning your water back on and allowing the tank to fill with water. Check the water level and listen for any running sounds. Adjust the float height if you need to and check again by flushing the toilet.

Problem Solved & Further Advice

Et voila! There you have it, a pretty handy list of the possible reasons you’re suffering with a nasty case of toilet constantly running-itis! We hope the steps above have been helpful, and if you still face a problem or would rather seek further advice then we recommend getting in touch with a trained professional. If none of these solutions for how to fix a running toilet work, then it might be time to call a plumber, or get your hands on a fancy new toilet.

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