Are Toilet Tanks Standard?

One of the most ignored pieces of furniture in your home is the toilet tank. Not the toilet itself, but the receptacle that holds the water so that when you flush your solid or liquid waste 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 an assorted number of odds and ends. But when it stops working, that is when it really gets our attention.

In our disposable world, many people choose to replace their entire toilet when it stops working. In most cases it is cheaper, and there are 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.

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

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

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 systems 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 reduce the amount of water used per flush.

Just from a general description of how each of the different flushing systems work, 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 is choosing a new two piece tank is making sure the inside will be able to properly fit and install the hardware.

Gravity toilets are your best chance for being able to replace a toilet tank with a universal fit. The reason is it has become and 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 it attached to the wall, then you can replace it with a universal model.

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 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 and don’t forget that regular maintenance can significantly reduce the number of problems that can occur with the tank.


  1. Joe b February 6, 2018
    • Jason Wilson March 19, 2018
  2. GFR February 10, 2018
    • Jason Wilson March 19, 2018

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