Are Toilet Tanks Universal? 

In contrast to the toilet bowl itself, the toilet tank usually needs replacement more often. This is because toilet tanks are actually what flushes the water down your toilet, so they are used frequently. If your toilet tank won’t fill or toilet leaks, it’s probably in the need of a replacement. But, how do you choose the proper toilet tank? Are toilet tanks universal?

Let’s discuss this topic for you to find the best toilet tank for your situation.

Are Toilet Tanks Universal In Size? 


Choosing the proper toilet tank usually comes down to the type of flushing system used. That being said, toilet tanks are not universal in size – at least generally speaking.

What’s important to know is that there are different categories of toilet tanks. Toilet tanks inside each of these categories are universal in size.

So, if you’re toilet tank needs a replacement, it’s important to first know the category of your own toilet system.

There are many types of flush systems available, especially with some of the new ones on the market. Among those, there are three which are the most common ones:

  1. The Gravity Flush Toilet

This is one of the oldest and most common flushing systems out there. Therefore, there’s a really high chance that this is the exact one that you’re having.

The name is self-explanatory – the flush valve opens up and the gravity lets the water run down the toilet bowl. This process is pretty simple and this makes the gravity flush system also gentle.

These kinds of tanks are typically cheaper than other tanks on the market. However, this doesn’t make them less reliable.

  1. The Pressure-Assisted Toilet

The pressure-assisted toilet tanks use pressure created in the tank to release the water down the bowl.

In other words, the water fills up the whole tank which is air-tight. This pressure created is what releases the water after the toilet handle is pushed.

The main advantage of these toilet tanks is that the pressure they create is high. This results in waste being pushed further than with the case of gravity system tanks.

  1. The Dual Toilet System

The dual flush toilets are particularly popular these days.

It allows choosing between using more or less water, by pushing either a bigger or a smaller button. The bigger one allows more water to be flushed, and the smaller one flushes less water.

It goes without saying, this is exactly what makes it an effective and environmentally friendly option. Not wasting more water than needed also takes care of your water bill.

Common Toilet Tank Sizes 


We’ve already answered the question of Are toilet tanks universal in size? They aren’t unless you’re talking about a specific category.

Once you’ve figured out the type of flushing system your toilet has, you can choose any toilet tank in that category.

However, here are some useful pieces of information about the toilet tank size gallons:

  • The length of small tanks is usually 15 ⅛ inches
  • The length of bigger tanks is usually 16 ¾ inches, with the width to 18 inches [1]
  • Really old toilet tanks could use about 13 gallons per flush, whereas…
  • Toilet tanks that were created after 1992 use only 6 gallons per flush (as it’s stated by the U.S. law) [2]

If you still want to be 100% sure to choose the proper tank size, then make sure to take note of the toilet brand. What you can also do is to take the measurements of your toilet.

You can take note of the toilet brand by inspecting the sides of the toilet bowl or the toilet tank. Sometimes, the brand name is written inside the lid of the toilet tank.

After you’ve found it, you can simply Google the toilet tank for the toilet brand you have.

You also want to make sure you got the measurements right. This is a crucial step that will make a toilet tank replacement process so much easier.

Make sure to include not only the width and length of the tank but also the depth of it. Consider the space between the toilet bowl and the waste pipe, too.

Do a so-called rough-in measurement –  measure the distance from the wall to the center of the waste outlet.

Universal Toilet Tank Replacement 


In this part of the article, you’ll learn some universal rules to replacing a toilet tank.

It can be frustrating when your toilet won’t stop running or water leaks between the toilet tank and a bowl. This is it’s very useful to know these skills.

To replace the toilet tank, follow these steps:

  1. Turn off the water valve that connects to your toilet. This is necessary in order to safely and successfully replace a toilet tank without any water gushing out.
  2. Drain the toilet tank. In order to drain the toilet tank of any water, you’ll need to flush, as you usually do.
  3. Disconnect the toilet tank. Depending on the type of the tank, you may need to disconnect it from the metal pipe.
  4. Remove the bolts on your toilet tank. This process might be a bit more complicated if you need to remove the rusted bolts.
  5. Detach the toilet tank
  6. Replace the bolts and rubber gaskets, if needed. If not, just adjust the same ones to the new tank.
  7. Install a new toilet tank. Proper measurements that you took prior to installation should help.
  8. Tighten the bolts
  9. Attach the water valve hose/pipe to the new tank
  10. Do the check. Flush the water to check if it works properly.

You’re all set! The toilet tank replacement is now finished.

Are American Standard Toilet Tanks Interchangeable? 

Checked for the brand and discovered that you own an American standard toilet tank? If so, you might wonder if it’s possible to mix the tanks and bowls of this brand.

As stated on the company’s site, most American standard toilets come in sets.[4] This means that you cannot match tanks and toilet bowls from different sets.

This is a rule for both gravity and pressure-assisted toilets. Be careful, as if you do this even by mistake, your toilet might not be functional at all.

Crane Toilet Tank Replacement

When speaking of crane toilets and toilet tanks, it’s usually under the name of Crane products overall. Crane plumbing products include a wide range of plumbing products that belong to the famous North American company.

Crane toilets have a “mix&match” system, which allows users to install their toilet bowls and tanks interchangeably.

In this case, the only thing to take note of is the toilet tank number. But, since American Standard & Universal Rundle started manufacturing for the Crane company, it’s important to check for the date, as well.


Are toilet tanks universal?

As discussed in the article, most toilet tanks are universal if chosen within their own category. Overall, they are not universal, as you usually can’t mix&match any toilet tank to any toilet bowl.

Are toilet tank parts universal?

Most toilet tank parts are universal. However, it’s smart to always take measurements to make sure they will fit your new toilet tank openings.

Are Kohler toilet tanks universal?

No, they are not interchangeable. Many previously interchangeable tanks have recently redesigned their bowls and tanks. This is why it’s best not to mix brands of toilet tanks and bowls.