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How To Install/Replace A Toilet Tank (5 Simple Steps)

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

As with most things used regularly, in time there’s a good chance that your toilet tank is going to feel the effects of constant use.

So whether it’s a crack, a leak, or perhaps just that it’s old and outdated now, you’re probably here because you need to learn how to install or replace your toilet tank.

Well luckily for you, you came to the right place. This article will have you switching your tank over with ease in no time at all. 

Now let’s get the basics down so you know what you’re dealing with.

Most tanks can be sold separately to the bowls and so you just need to find yourself a tank thats going to fit the model of your toilet (see also our guide to rear outlet toilets) bowl.

These tanks are usually mounted upon the bowl using around two or three bolts.

These bolts usually have a rubber and metallic washer behind them, this is so that you don’t end up with a leaky and wobbly toilet (see also ‘How To Fix A Wobbly Toilet In Five Easy Ways‘), because lets face it, that is ideal for nobody. 

There is also a gasket for the tank and bowl which is intergrated on the exterior of the flush valve.

This stops the toilet leaking. The tank attaches to the water shut off valve through a supply line. 

So, now that you’re all updated on general toilet-tank knowledge, lets get into what you’re going to need to get the job done. 

Gather The Materials

How To Install/Replace A Toilet Tank (5 Simple Steps)

Okay, so below I’ve compiled a list of everything that you’re going to need before you can officially start installing or replacing your tank.

So get your checklist ready, make sure you have everything you’ll need and we will meet back at Step One! 

  • A Fresh Tank for Your Toilet
  • A New Gasket for Said tank
  • All Miscellaneous Parts for the Tank
  • Bolts, Nuts, And Washers (again, for the tank)
  • An Empty Bucket
  • A Sponge
  • A Flathead Screwdriver
  • Wrench (adjustable)

Step One: Turn Off The Water

Okay, so now that you’ve got all your materials. Lets start with the first and most simple step.

You need to turn off the water access of the toilet. Around the back of the toilet, you should be able to find a valve.

It should be fairly near the ground to the left of your toilet. 

Got it? Great, so now you’re going to want to turn it clockwise. This will turn off the water. 

Some toilets may have push or pull valves, if yours does, instead of turning clockwise youre going to want to pull the handle out towards you. 

And thats it! Step one done! 

Step Two: Drain The Tank 

On to step two! Next you’re going to need to drain the water out of the old or damaged tank. This is a lot easier than it sounds. 

First of all you’re going to want to flush. While flushing the toilet, hold down on the handle so that you can force the greatest volume of water out to drain. 

Next, you’re going to want to take off the toilet tank’s lid and move it somewhere out of the way. 

There’s nothing more annoying than trying to get on with a job and there’s clutter everywhere. 

If you have a peek under the lid, you’ll see that there’s still some excess water that didn’t quite flush away.

This is where you’ll grab your sponge and your bucket.

Soak up all the extra water and squeeze it out into the bucket unil the tank is completely empty. 

Once you’ve done this, you’ll need to disconnect the water supply line. You’re looking for a braided line crafted from stainless steel.

It will be attached via the shut off valve of the toilet tank. It’s usually linked up with what’s known as a fill valve, from the bottom of your toilet tank. 

Here’s a little tip for you – if you loosen the coupling with your hands before you use the wrench you’ll find the task a whole lot easier. 

Step Three: Remove The Damaged/Old Tank

How To Install/Replace A Toilet Tank (5 Simple Steps)

So, you’ve drained your tank and are now on to step three! You’re doing great!

What you’re going to need to do now is remove your old and damaged toilet tank

As mentioned earlier, this will be attached by two or three long bolts, depending on the model.

These run through to the tank’s internals where they can be tightened from the bottom of the toilet bowl with nuts and washers. So how do you go about removing the tank? 

First, grab yourself a wrench. An adjustable one works best.  You’re then going to try and loosen the nuts keeping the tank attached beneath the basin. 

If you haven’t had to change your tank before, there’s a good change that these nuts might be a little corroded or super tight.

If they are, you’re going to want to use an oil that can penetrate the disrepair. It will loosen those nuts right up.

WD40 is a great choice – just leave it for around 10 to 15 minutes and then get back to it and it should be much easier now. 

If your bolt is so far gone that even WD40 could not save it, you’ll need to try and find a hacksaw blade (the whole hacksaw won’t fit) or something similar to cut that nut off. 

Contrastingly, if the nut seems to be swiveling you can always grab a screwdriver, preferably a long one, to hold it from inside the tank while you work on the nut with a wrench below.

If you’re struggling to do this by yourself, you could always ask for a trusty volunteer to try and take over holding the screwdriver. 

Once you’ve finally got the nuts out, the tank will be loose enough for you to lift it straight out of the toilet. 

Step Four: Install The New Tank

Well, you’ve made it most of the way, so now it’s time to get that new tank installed.

One thing I would always recommend is that when you’re installing a brand new tank, make sure you also get a brand new gasket as well as new washers and nuts.

If you don’t there’s a good chance that it wont hold as well and you’ll end up with a leak. 

The first thing you need to do is very carefully lay the tank onto its side on a stable and flat surface.

If you do this on top of the toilet bowl, you’re probably going to crack the new tank.

And that’s just creating extra problems and expenditure for yourself that you don’t need. 

Next, you’ll want to grab a tank bolt, and place a steel and then a rubber washer. Repeat this for all the bolts that you have. 

Then from the inside, place the bolts into the corresponding toilet tank holes.

What you’re hoping to do here is make sure that only the rubber tank touches the actual tank.

You’ll do this so that if you do overtighten any nuts or bolts, you don’t end up cracking it.

If you look, on the bottom of the tank you’ll find a place where you can pop a rubber washer on all of the bolts.

Then do the same with the steel washer and nut. Like before you only want the rubber washer to ever actually come surface to surface with your tank. 

Next tighten the nuts with your hands. Once they’re fairly tight, pop the screwdriver into the tank and tighten the head of each bolt.

Next, secure the nut from the outside with your wrench. 

The valves on your new tank should be preinstalled already. The only thing you’ll need to do is just double check that the fill valve lock nut is nice and tight.

Next grab the gasket and make sure it veils the lock nut completely. 

Once all of this is done, you’re ready to lift the toilet tank (see also ‘How Do You Remove Rusted Bolts From A Toilet Tank?‘) to mount to the upper bowl.

Make sure that you carefully direct the bolts into the holes in the bowl. 

Now that it is sitting correctly, you can install a rubber washer, steel washer and nut to each of the bolts under the bowl.

Alternatively tighten both of these with a wrench until it’s secure.

Now it is important that you alternate as you secure the bolts to make sure that the tank remains balanced and level.

A wonky tank is not ideal. Also, remember to do everything nice and gently or you’re going to crack the bowl. 

Step Five: Reconnect The Water Supply

How To Install/Replace A Toilet Tank (5 Simple Steps)

Congratulations! You’ve made it to the very last step so you’re so close to being done!

All you need to do now is reconnect what we disconnected earlier on. 

Reconnect your toilet and water supply line, making sure that it is only hand tight as using a wrench might deform the line. 

Now turn the water shut off valve back on and wait for the tank to fill with water. 

Then all that’s left to do is give the toilet a few flushes and make sure nothing is leaking. 

And that’s it! Give yourself a pat on the back. 

You did it! 

Kohler Tanks

Now these tanks are built a bit differently than your standard tank. So therefore installing them actually uses a different method. 

One of the main differences being that these tanks don’t have holes for your bolts.

Instead they have something called a DryLock method.

Basically, Kohler uses a bracket at the bottom of the toilet where the bolts are then hooked. 

You’ll be using three bolts for Kohler tanks.

Then you need to get the bracket bolts nice and straight, and then you can place the tank on the bowl.

Once you’ve done this, just tighten up the bolts with nuts. 

These are a lot quicker to install and prevent toilet leaks, so they are a much better option. 

Frequently Asked Questions

Can You Interchange Between Brands When Buying A Toilet Tank? 

This is a common question that people have when buying a toilet tank (see also ‘ Best Epoxy For Toilet Tank Repair ‘).

My advice is that is is always of you best interest to stick with the same manufacturer because while on the outside they can all look fairly similar, it can be very different inside, and it may not actually match up. 

Are Toilet Tank Bolts Universal? 

Toilet tank bolts are usually fairly standard and so should fit most types of toilets. 

What Size Are Tank To Toilet Bolts

Usually they’re about 5/16” by 2 ¾” in length. They are proven to be very durable and sturdy too.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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