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How to Stop a Toilet Leaking from the Tank: A Step-by-Step Guide

How to Stop a Toilet Leaking from the Tank: A Step-by-Step Guide

If you have been hearing an endless trickling noise from your toilet, it may require repair, as this is an indicator of a leaking tank. A toilet leak can be attributed to many things: For instance, the leak may be coming from your tank, but the exact point from which the water is leaking could be the tank-to-bowl gasket, the flapper, or a bolt. Here is a step-by-step guide to fix this problem ASAP.

How do you fix a toilet leaking from the tank? To stop a leak from the toilet tank, follow these 6 steps:

  1. Disconnect the water supply and empty the tank by flushing.
  2. Remove the bolts and gaskets.
  3. Remove the tank and lay it on its side on a flat surface. Clean around the holes if necessary.
  4. Replace the tank components making sure to hand-tighten so as not to break the porcelain.
  5. Reinstall the tank and reconnect the waterline.
  6. Refill the tank and check for leaks.

Noticing your toilet needs repair before it’s too late can be tricky. Not everyone notices the trickling noise, and that noise is not guaranteed to happen, especially if the problem is not the flapper. It’s also important to know other possible causes of your toilet leaking, so for a thorough explanation of how to troubleshoot problems with your toilet, along with fixing the leak, take a look at the detailed guide below.

How to Tell if Your Toilet Tank is Leaking

Unfortunately, it can be quite tricky to tell if your toilet bowl is leaking. Many people don’t realize it until they get an unusually high water bill. A leaking toilet will cause water to trickle down from the tank into the toilet bowl almost endlessly. This will result in a massive waste of water that can not only create faster wear on your toilet’s components but also push your water use off the charts.

Thankfully, it is not too difficult to check for a water leak early on, before it gets to this point. Usually, you can attribute a leaking toilet to a broken flush valve (also known as the “flapper”). The flapper is meant to keep water from flowing into the bowl, so any failure of this component will lead to water flowing when it should not be.

When you flush the toilet, the flapper should open and allow new water to flow into the bowl to replace the water being lost to the drain. A damaged flapper will remain open either because its mechanism will no longer allow it to close or it is simply unable to hold a proper seal due to age.

To test for a leak in your toilet:

  1. Remove the lid from the tank.
  2. Locate the flapper at the bottom of the toilet tank. Note any damages or irregular positioning or behavior of the flapper.
  3. Add a few drops of food coloring to the tank. (The color does not matter; however, you need to be able to see the color clearly.)
  4. Wait for the food coloring to distribute itself throughout the water present in the tank.
  5. After several minutes, check the toilet bowl. If you see any colored water in the bowl, you can confirm that you have a leak from the tank.

How to Stop a Trickling Toilet?

Although fixing a leaky toilet is among one of the last things any homeowner or renter wants to do. Luckily it’s not too difficult of a job. Once you have the proper tools handy and know what to look for, you will have your toilet fixed and working like new in no time. Follow the guide below for intuitive instructions on how to fix your leaking toilet tank.

1. Find the Source of the Leak

Even if you know for sure that the leak was coming from the tank, it is highly recommended that you fully inspect your toilet just to be sure. This is because there is more than one location from which a toilet can leak. They are:

  • The base of the toilet.
  • At the main water connection.
  • In the tank (via the bowl connection or gasket)
  • From the bolts

Of all these possible sources, a leak from the base of the toilet or the main water connection will be the easiest to spot. This is also why a thorough inspection is in order, as it is slightly more difficult to identify a leak from the tank. Thoroughly inspect the area to not only find the source but to determine the tools you will need.

Pay close attention when you look at the site between the tank and the bowl: If the leak is indeed coming from here, you will be able to feel water at this site. This will confirm for you that the leak is coming from the tank bolts. With this confirmation, you need to gather the proper tools.

2. Determine the Proper Tools for the Job

Now that you have thoroughly inspected the source of the leak, you have an idea of what tools you are going to need. To fix a toilet tank’s leak, you will need to either purchase a pre-made toilet tank-and-bowl kit or put one together yourself. You will need:

  • 5/16” x 3” tank bolts
  • Nuts (they can be standard nuts or wing nuts)
  • Washers (and tank-to-bowl washers)
  • Gasket
  • Locking pliers (optional for severely rusted bolts)
  • Wrench
  • Slotted screwdriver

3. Empty the Tank

Next, you will need to shut off the supply valve so that you can safely remove the tank for repair. Turn the shutoff valve in a clockwise direction to turn it off. Next, flush the toilet to allow the tank to empty, making it easier to find the source of the problem and fix it. Once empty, you need to remove the tank entirely.

After you’ve emptied the tank with the flush, use a sponge to soak up any remaining water that was left in the tank. This will prevent any water from spilling out when you go to remove the bolts.

4. Disconnect the Water Supply

Now that the tank is empty, you need to disconnect the water supply line. You can choose to do this before or after unscrewing the bolts of the tank. Depending on the type and condition of your water supply line, you may be able to remove it with your hands alone. Still, it is best to be prepared to remove it with a wrench or channel lock pliers.

Be aware that even if you removed all the water you could when emptying the tank, there’s a chance that the ballcock will leak.

5. Remove the Tank

Now you need to remove the nuts and bolts that hold the tank in place. They should not be too tight since it is typically recommended for these to be hand-tighten to avoid breaking the porcelain.

Still, depending on the age of your toilet, these may not be in good condition and may require a bit more effort for removal. Depending on the condition of your bolts, you can choose to remove them in two different ways:

  • There is a slot at the top of these bolts for you to place a slotted screwdriver. This is meant to keep the bolt in place while you unscrew the nut underneath it. If the bolts are in somewhat of a good condition, you can remove them this way.
  • If the bolts are especially rusted, you will need to remove them by spraying the bottom of the tank with lubricant to help you in unscrewing them. Next, you will need to use locking pliers to keep the bolt in place as you unscrew the nut below. In this case, it is best to have someone help you.

When you have removed the nuts and bolts from both sides of the tank, lay the tank down for the safest handling. It is recommended that you place lay the tank on one of the wider sides either on top of the toilet bowl or another flat surface that is close to the toilet. Remaining close to the toilet as you work will prevent any risk of you dropping it when you go to put it back into position.

6. Replace the Tank-to-Bowl Gasket

This step is optional as it may or may not be the (or one of the) sources of your toilet leak. Since you should be inspecting each component of the toilet as you take it apart, you will notice if the gasket needs to be replaced. Old, warped gaskets – even if they are not yet leaking – need replacement.

Leaving them in place will only delay any problems from this component in the future. Since you’ve already gone through the trouble of removing the tank and many toilet bowl/tank kits include a gasket, you might as well replace it.

The type of gasket you use to replace the old one may differ in size and depth. The lip of the gasket can be shallow or quite deep, and the advantages of each comes down to the style or your toilet and your personal preferences. Gaskets that are deeper, tend to achieve a stronger hold over the nut and may, therefore, be more efficient at preventing leaks.

If you are buying your toilet bowl/tank kit in person, you should be able to get a general idea of the size of the gasket by simply looking at the components in the packaging. Since they both work generally at the same level of efficiency, it ultimately comes down to your preference.

7. Reinstall the Tank Components

Before you begin installing all of the new components, you need to make sure the tank is clean and ready for operation again. To do this, use a wire brush to get rid of any residue, especially rust, that may be lingering. This is highly important, as you will need a clean surface to achieve a strong seal.

You will need to install:

  • One bolt
  • One washer
  • One rubber washer

These components will all go on the inside of the tank. This will be repeated on the side of the bowl, but instead, with a gasket, washer, and nut.

  1. Take the bolt in your hand and first thread the metal washer onto the bolt.
  2. Next, place the rubber washer onto the bolt. This will protect the metal from having direct contact with the porcelain, preventing any further damage to your toilet.
  3. Now with the washers on, place the bolt through the hole from the inside of the tank.
  4. Thread onto the bolt the last metal washer from the outside.
  5. After this washer, tighten the setup with a nut using your hands.

If you want to reinforce your set up, you can opt to use any extra nuts and washers you may have to secure the tank from the outside even more. For some, this double-gasket configuration may work better than before. If you prefer to use a wrench when tightening these bolts, simply pay extra attention while you’re doing so.

Tighten in very slow progression, watching the porcelain intently with every turn. It is easy to loosen the bolt if you feel that it is stronger than what is appropriate, but you cannot come back from a cracked tank. You must take your time.

8. Reinstall the Tank

Now that you’ve reinstalled the essential components, you are ready to put the tank back into position.  At this point, it is also important to remember that it is recommended that the nuts are tightened by hand to avoid breaking the porcelain.

This step is much easier with a helper, as they will be able to hold the tank down and in position as you tighten the nuts from underneath the tank. Alternate between each side of the tank as you tighten the nuts and bolts to ensure that the tank is evenly balanced and the gaskets are perfectly seated.

9. Reconnect the Water Supply Line

Now that the tank is back in position, you can reconnect the water supply line.

This is another task to which you need to pay very close attention, as you can damage or completely break the ballock if there is too much force. This will just cause another leak for you to have to repair in the future, so it is best to take your time, even though it seems like a fairly straight-forward step.

10. Refill Tank and Check for Leaks

With everything back in place, you need to reopen the water supply line and check for leaks. You can do this either by simply observing and listening with a few flushes or by using the food coloring method outlined at the beginning of this guide.

Some key places to check for leaks are:

  • Near the main water connection
  • The newly installed tank-to-bowl gasket
  • Each of the new bolts

If there are leaks at any of these locations, it can mean that you’ve either not tightened them enough, you may have cracked the porcelain, or there was a mistake in the positioning of a component. Adjust your set-up as necessary to stop any leaks you observe.

Can a Toilet Leak Without You Knowing?

Toilet leaks are one of the most common reasons why so many people are facing surprisingly high water bills. It is not always easy to notice whether your toilet is leaking, and oftentimes people simply don’t know what to look for. If you notice any of the following, your toilet may be the culprit for your rising water bill:

  • You have to jiggle the lever so the toilet will stop running.
  • Your toilet continues making noise even when it is not in use.
  • The tank will not empty unless you are holding down the lever.
  • “Ghost flushing:” the toilet sounds as though it is flushing on its own.

Toilet leaks can be difficult to notice, but it doesn’t have to go on too long without you noticing. All of these are major indicators of a leak in your toilet that unfortunately not many people are attuned to. Becoming familiar with these signs will help you to catch the leak early on and prevent any further wasting of water.

What Causes a Toilet Tank to Stop Filling Up with Water?

There are two main components that are meant to keep your toilet from constantly filling and flowing with water: the fill valve and the flapper.

How the Fill Valve Works

The toilet fill valve is located on the left-hand side of the tank. It will appear to be a sort of cylindrical tower with the valve itself located at the very top. The fill valve is responsible for controlling the water level in the tank. Any water that is stored in the tank flowers into the bowl when the level is pushed. Once the tank is empty, the fill valve then begins to allow more water back into the tank.

This mechanism of refilling the tank is controlled by a component known as the float ball, which is attached to the fill valve by a metal rod. Given its name, you can probably guess what this component does: it floats atop the surface of the water, rising along with the water level which forces the connecting metal rod into the valve.

The valve then shuts off when the metal rod makes contact with its switch. If the float ball lowers at all, the metal rod will lose contact with the switch and water will begin flowing into the tank once again. If your fill valve is having trouble filling the tank (or will not stop filling the tank), there are two possible causes:

  • The mechanism may be rusted
  • There may be a calcium build-up

You can quickly solve this issue by moving around the tower on which the fill valve is located. This will break free any calcium or rust build-up around the mechanism. If it continues to leak after this, however, you will need to replace the valve altogether.

How the Flapper Works

The toilet flapper is much simpler than the fill valve. This round, rubber component can be on the very bottom of your toilet tank. The flapper is attached to the overflow tube by mounting arms hooked on either side of the tube.

When you flush, the flapper allows water to flow from the tank into the bowl by lifting and breaking the seal with the connection to the bowl. A flapper in working condition should be able to close and reform this seal with ease, stopping any unwanted water flow. If it has become warped or otherwise damaged, it will be unable to properly close and result in constantly flowing water into your toilet bowl.

To check the flapper’s functionality, you can pull the chain attached to the top of the flapper and watch closely to see how the flapper opens and closes.

Why is My Toilet Leaking from the Bottom?

When you are troubleshooting for sources of your toilet leak, remember that the base is another site at which a leak can occur. You may have fixed the tank leak, but if you are still noticing excessive water use or other signs of a malfunctioning toilet, this may be the reason.

One of the most reliable signs of a leak from the base of your toilet is the presence of water around the base of your toilet. To begin to rectify the issue of a leaking base fixture, turn your attention to the plastic caps that are typically overlooked when inspecting the toilet.

These caps cover tee bolts that are responsible for keeping your toilet in its proper position. If the tee bolts happen to loosen over time or becoming damaged or rusted, this creates the perfect scenario for a leak. To fix a leak from the base of your toilet:

  1. Shift your toilet so that it is centered and properly balanced.
  2. First attempt to tighten the tee bolts. If the leak stops, it was simply due to loose bolts. If it continues, however, follow the remaining instructions. (If the bolts spin rather than loosen, they will need to be replaced.)
  3. Shut off the water supply to the toilet and flush the toilet to drain it completely.
  4. Remove the excess water from the base by plunging it a few times.
  5. Detach the water supply line and remove the tee blots.
  6. Lift the toilet and set it gently on its side to remove the wax ring.
  7. Replace the wax ring with a new one by placing the new piece over the flange with the tee bolts in place.
  8. Place the toilet back into its proper position.
  9. Adjust the positioning of your toilet until it is perfect and has a strong seal to the new wax ring.
  10. Screw in the tee bolts without overtightening.
  11. Reconnect the waterline and flush to check for any remaining leaks.

How to Troubleshoot for Common Toilet Problems

As you’ve seen in this guide so far, there are many points of connection and seals through which a toilet may leak. You may be lucky to find that the leak is attributed to only one component, or troubled to find that many issues have developed with your toilet over the years.

Either way, you need to know how to troubleshoot these problems to prevent and fix them in the future. Below are some of the most common problems homeowners come across with their toilets and how to test for them:

  • Phantom flushes: Now and then you may hear your toilet suddenly refilling seemingly without provocation. This is indicative of a slow leak coming from the tank, flowing down into the bowl. Since this is the primary issue discussed in this guide, we won’t go into detail here about troubleshooting for and solving, this one.
  • The bowl is slow to empty: This is also known as a “weak flush” and can be attributed to clogging underneath the rim of the bowl. This is a simple fix: grab a curved piece of wire, a coat-hanger will do, and gently prod into the holes to free them of any residual debris. You can do the same thing to the siphon jet located at the bottom of the drain.
  • Leaking seals: On a standard toilet, there are at least five seals that could potentially leak – that’s a lot to keep track of! The largest seal, of course, will be the one that connects the tank to the bowl. However, a break here will be easier to spot than any other, as water will be shooting out quite forcefully after each flush. Check for leaks by looking or feeling for water around the bolts and gaskets.

Knowing how to properly troubleshoot and identify problems with your toilet will prevent you from having to deal with any problems of waste in the future and protect you from high water bills. Just make sure to keep a close eye on your toilet’s behavior, and it should remain in top working condition.


How to know if your toilet is leaking

How to Fix a Toilet Leaking from the Tank Bolts

Why is My Toilet Leaking At The Base?

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