toilet tank

Are Toilet Tanks Universal?

When was the last time you paid much attention to your toilet tank? Though this is one of the least-noticed parts of the toilet, it’s among the most important.

Your toilet tank stores the water needed for a flush, and it is responsible for your overall flushing power.

You might be tempted to replace your whole toilet if you notice that you have a less powerful flush. Similarly, you might think you need to toilet shop if your tank becomes damaged or broken.

But in many cases, you actually can replace your toilet tank, especially if you know that it’s the source of the problem.

So are toilet tanks universal? Unfortunately, the answer is no.

However, you may be able to get an interchangeable tank depending on the brand, the dimensions, and what type of tank it is. Your first step will be to research the type of toilet that you have.

Can You Put A New Tank On An Old Toilet?

putting new tank

In many cases, you can put a new tank onto an old toilet. There might be an exception when the toilet is sold as a fused tank-and-bowl unit, though.

When this is the case, you might not be able to remove and replace the tank.

However, if your toilet tank can be removed, then it can be replaced. You’ll want to make sure that replacing it is worthwhile first.

That means that the rest of the toilet should be in good working order. If your whole toilet needs repairs, it might be cheaper to buy a new one.

You can purchase a new toilet tank to put on your old toilet. You’ll need to drain the old tank, unscrew it, and remove it.

Then you’ll need to follow the manufacturer’s instructions to put your new tank in place and waterproof it.

The biggest thing is making sure that the new tank is compatible with your toilet. It needs to have the same dimensions as the old tank.

It can also be helpful to get the same model from the same brand that made the original tank.

How Do I Know What Size Toilet Tank To Buy?

If your toilet manufacturer does not have interchangeable tanks, you will need to take some measurements. There are certain standardized sizes for toilet tanks, but they vary depending on the type and size of the toilet itself.

The important measurements include the height, length, and width of the tank. The largest size ranges tend to be around the length.

The toilet tank is often sized proportionally to the bowl, so smaller bowls will have a smaller tank. This is because they need less water and power per flush.

Types Of Toilet Tanks

There are three main types of toilet tank, which are divided based on the flushing mechanism. If you’re replacing your tank, you’ll want to make sure that you get one that aligns with your toilet type.

Getting the wrong type could harm your plumbing or result in an unflushable appliance.


gravity flush toilet

Gravity flushes are among the most common models installed in residential homes.

With these toilets, you’ll find a lever at the front of the tank. This is used to flush. On the bottom of the tank, you’ll find two holes.

One hole is used for connecting to your toilet bowl, while the other is an intake pipe for the water.

As the name implies, this type of toilet uses gravity for its power. The water flows powerfully downward and then is deposited into the waste pipes, which typically run below the toilet.

Pressure Assisted

pressure assisted toilet

Pressure assisted toilets are a little more complicated. The tank looks very similar to a gravity tank.

However, these toilets are typically installed in basements and other areas below the sewer lines.

Since the water can’t flow down to the sewer, it needs to be pushed up.

That’s where the pressure assistance comes in. This tool goes inside your toilet tank.

As it fills with water, it uses pressure to push the toilet’s contents up to the sewer line.

Dual Flush

dual flush toilet

A dual flush toilet operates very similarly to a gravity toilet in principle. Because of this, you may sometimes be able to interchange dual flush and standard gravity tanks.

The big appeal of a dual flush toilet is energy efficiency. Rather than having one lever, it has two buttons.

You press a different button depending on whether you’re getting rid of solid or liquid waste.

This helps you save water when you’re flushing liquids, while still giving you the flushing power that you need to get rid of solids in the bowl.

Are All Toilet Tanks Standard Size?

Toilet tanks do not have a standard size. There is no standardization requirement, and different sized toilets might have different sized tanks.

Larger bowls need a larger tank, for example.

Different manufacturers often have standardized sizes for their own toilet tanks. But if you aren’t sure what model your toilet is, it’s best to measure the dimensions of your tank by hand to be sure.

Tanks can range in length from 15 to 19 inches, though they’re much more commonly in 15 to 16.5 inch range.

How Do You Measure A Toilet Tank?

how to measure toilet tank

The first measurement will be from the floor to the top of the tank. Then you should measure from the floor to the seat.

Subtract the second measurement from the first, and you have the basic height of the tank.

The next measurement will be the length of the tank. Small tanks are often around 15.125 inches in length.

Large tanks might range anywhere from 16.75 to 18 inches in length. It’s vital that you get as precise a measurement as possible using a tape measure.

You’ll want to measure the width of the tank as well. This is the length from the wall to the front of the tank.

How Do You Know If A Toilet Tank Is Compatible?

Toilet tanks should be compatible with your toilet if they’re the same type and have the same dimensions. In some cases, it’s easiest to buy a replacement tank for your toilet from the manufacturer who made the original tank.

That way, you can be sure that you have the exact correct model.

Can You Mix and Match Toilet Bowls and Tanks?

The question of whether you can mix and match toilet bowls and tanks depends on a few factors.

First, you cannot mix and match toilet tanks that are of different dimensions. Your toilet bowl is built to work with a tank that has specific dimensions.

If you get the wrong sized tank, not only will you struggle to install it, but you might not have the correct flushing power or plumbing.

In addition, the type of toilet matters. There are different tanks that serve different purposes.

If you have a gravity fed toilet, you cannot use a pressure assisted tank. The reverse is also true.

These types of parts are not compatible. If you try to put these components together, you’ll find that your toilet doesn’t even flush.

You should always make sure that a tank is compatible with your toilet bowl before you purchase one. The best thing to do is to use the recommended tank model with your toilet bowl, rather than trying to mix things up.


Are Kohler Toilet Tanks Interchangeable?

Kohler toilet tanks are not interchangeable. When you shop for a Kohler toilet, there are warnings about mixing up the bowls and tanks.

You should only use the approved Kohler tank model with a Kohler toilet bowl.

Are American Standard Toilet Tanks Interchangeable?

According to American Standard, it is possible to interchange a few of their toilet tank models. However, they don’t recommend doing this. In addition, not all of their tanks are standardized or interchangeable.

Their website has strict guidelines regarding which models can be interchanged. They also note that you’ll get the best performance if you use their default configurations instead of trying to do a DIY mix and match.


Replacing a toilet tank can be a pain, but if the rest of your toilet works fine, then the investment is often worth it. But it’s important to know that toilet tanks are not universal.

Because of this, you’ll need to measure your toilet tank prior to buying a new one.

In addition, some types of tank are incompatible. If you aren’t sure what type of toilet you have, your best bet is to find out what tank is recommended for your model.

That way, you know that you aren’t accidentally choosing an incompatible option.

If you really aren’t sure where to start with replacing your toilet tank, you can also contact a plumber. They’ll be able to find out the model and tell you whether it’s better to replace the tank or get an entirely new toilet.