Are Toilet Tanks Standard?

One of the most ignored appliances in your home is the toilet tank. Not the toilet bowl itself, or even the toilet seat, but the receptacle that holds the water so that when you flush your solid or liquid waste, it finds its way into the sewer line and away from your house.

We may lean on it, cover it, or most commonly, use it as a shelf where we put toilet paper and an assorted number of odds and ends. But it’s only when it stops working that it really gets our attention.

If your toilet tank stops working, can you replace it? Furthermore, are toilet tanks standard?

In our disposable world, many people choose to replace their entire toilet when it stops working. In most cases, it’s cheaper, and there are constant advances in plumbing technology that can be taken advantage of for a more sanitary, water-saving toilet.

A little secret many people do not know about is that toilets simply wear out after a number of years. So attempting to replace your toilet tank should only be done after you know it is the problem.

Think your toilet tank needs replacing?

In this article, we will provide a guide to identifying the type of toilet tank that you have, and how to replace it. Many people wonder whether toilet tanks are “standard”, as in, can I replace one water tank type with the other?

The short answer is no, but we will explain why below, as well as explain the specific differences in toilet designs that account for this.

Then, we will explain some common problems you may have with your toilet tank, and how you might be able to solve them without needing a replacement at all!

(If you do need a replacement, be sure to look into whether your old toilet can be recycled.)

Types of toilets

In order to know the right type of toilet tank to buy you need to know the type of flushing mechanism you have. There are three basic types:

  • Gravity
  • Pressure assisted
  • Dual flush

Below, we will explain each type, and then explain why they are not necessarily interchangeable. Toilet repair is not always an easy task, but it is essential to do it properly because the last thing you want is a leak in your bathroom (or worse).


Most people know about the gravity flushing systems since they are the most common found in homes.

The flush lever is on the front side of the tank, and there are two holes in the bottom – one for the water intake pipe and the other that connects to the toilet bowl as the water outlet source.

And of course, it uses the power of gravity to generate its flushing power.

Pressure assisted

The pressure toilet has the same water intake and outlet holes as the gravity unit, but instead of using the pulling force of a gravity toilet.

There is a single unit placed inside the tank that fills up with water and pushes the contents of the toilet into the sewer line using the water in the tank.

Dual flush

Dual-flush toilets are becoming increasingly popular, and their design is similar to the gravity toilet. The major difference is that there are two buttons on the top center of the toilet tank, one for liquid waste and one for solid waste.

The goal is to conserve water by reducing the amount of water used per flush.

Which type do I need?

Just from a general description of how each of the different flushing systems works, it is clear that there is not a one size fits all approach to choosing a toilet tank.

One rule that applies to all types of flushing systems is that you will have a choice between a one-piece model and a 2 piece model.

If you choose the one-piece model and the toilet tank needs to be replaced, you will have to replace the entire unit.

The major consideration in choosing a new two-piece tank is making sure the inside will be able to properly fit and install the hardware.

Gravity Toilets

Gravity toilets are your best chance for being able to replace a toilet tank with a universal fit. If you need a replacement for this style toilet tank, you should easily be able to find it in a local store.

The reason is it has become an industry-standard, so most if not all of the inner pieces you currently have will fit into the new tank without a problem. Just be sure to check and see if your toilet has any unique features.

There are also toilet tank models that attach to the wall with screws. If you judge that there is no longer a need to have wall-hung toilets, then you can replace it with a universal model.

Pressure Assisted Toilets

All pressure-assisted toilets have one thing in common when it comes to replacing a toilet tank: the tank you choose must comfortably fit the water collection unit inside the toilet tank.

This may require you to buy a replacement tank only from the manufacturer. Also, be sure to make sure it is the same model. Pressure assisted tanks can be placed on the floor or rest on the toilet as with the standard gravity types.

Dual flush models are much the same as gravity models except you need to make sure the top of the tank has an opening for the flushing mechanism.

So are toilet tanks standard?

The best answer to the question is – it depends. The more standardized your unit is, as with a gravity toilet, the better the chances are you can find a replacement tank without any trouble.

Since dual flush systems are becoming more popular, they rank second, and pressure-assisted unit may require some searching.

Whatever type of toilet you have, keep the owner’s manual handy. Regular maintenance can significantly reduce the number of problems that can occur with the tank.

We wish we could say that toilet tanks are all standard because that sure would make life easy. However, if there’s one thing to take from this, read the manual and know what you are dealing with from the start.

If you learn how to replace your toilet tank right as you are installing it, you can save yourself a lot of trouble in the long run.

Common issues

Throughout this article, we have mentioned that there are several potential problems that could lead to a tank needing replacement. Therefore, it might be helpful to run down a few of the more common problems.

If you are aware of what could potentially go wrong, you’ll know how to avoid it. Some of these problems don’t even require a tank replacement at all.

Toilet Flushes On Its Own

If you’ve ever noticed your toilet flush out of nowhere, you may have a problem with the toilet tank.

This issue is caused because the toilet tank is slowly leaking water into the toilet, emptying itself, and then refilling on its own as if it had been flushed.

While this may seem like an issue with the toilet tank, it is actually generally a cause of the flapper. The flapper is meant to seal the tank from leaking water into the bowl.

Usually, if you clean the flapper, the problem will resolve, and you won’t need a new tank at all!

Water “Trickling” In Tank

If you constantly hear water trickling into your toilet tank, you may think there’s something wrong with the tank. This is not always the case, often it is the result of water coming in through the inlet valve.

It may also be caused by the refill tube being inserted too far into the overflow tube. Finally, it may be the result of a malfunctioning ballcock assembly.

As you can see, these problems do not require replacing the tank. In fact, often your toilet simply has problems with the mechanisms within it.

This is worth looking into before you splurge on an all-new tank. Unless your tank is noticeably broken or leaking, you can likely find the solution somewhere else.

The toilet tank replacement process

So you’ve read this far and come to the conclusion that your toilet tank does in fact need replacing. Replacing a toilet tank is something most reasonably handy homeowners can do.

It may simply require a quick trip for supplies that most hardware stores should carry. Here we’ll give a brief explanation on how to do this.

  1. Turn off the water supply to the toilet using the water valve.

  2. Drain the water from the tank and the bowl by flushing the toilet.

  3. Take off the toilet tank lid. Loosen the nuts on the bolts attaching the tank to the bowl.

  4. Lift the tank off the bowl and place it somewhere out of the way.

  5. Carefully put the new tank in place, matching up its mounting holes with the holes in the bowl.

  6. Slide a rubber washer over each of the mounting bolts, inserting them into the tank from the inside.

  7. From behind the bowl, slide the metal washer over the end of each bolt. Turn the nuts onto the bolts.

  8. From inside the toilet, insert a screwdriver into the bolt and carefully tighten the nuts.

  9. Using the water valve, turn the water supply back on. Flush the toilet to ensure there are no leaks.

Final thoughts

So there you have it. The answer to the question “Are toilet tanks standard” is: it depends. It really will depend on which type of tank you have, and how standardized your unit is.

Therefore, our best advice for you is to familiarize yourself with the tank upon installation. What better time to learn about the specifics of your toilet than when you are already installing it anyways?

Learn More About Toilets

Now that you’re up to speed on toilet tanks, there’s a lot more to learn about these vital fixtures of your bathroom.

Catch up in toilet history by learning when toilets became common, how toilets changed over time, why toilets used to be outside, and how toilets worked in castles.

Then debunk some common toilet myths by finding out whether toilets really flush backwards in Australia and if toilets can explode.

Finally, find the perfect toilet for your new home by learning whether toilets come in different heights and solve winter issues by learning what to do when a toilet freezes.


  1. Joe b
    • Jason Wilson
      • Tammy Morris-Traylor
  2. GFR
    • Jason Wilson
      • Fred Kerrick
  3. Harold CHORNY
  4. Wayne Floyd
  5. Wayne Floyd
  6. amy wu

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