Are Toilet Tanks Universal? [Don’t Waste Your Money!]

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Toilets aren’t exactly light on the pocket. When our toilet tank goes wrong, we would like to replace the tank instead of the whole unit. Are toilet tanks universal? Or should we have to get one with the same brand and serial number?

are toilet tanks universal

Unfortunately, toilet tanks are not universal. Even though the tank sizes don’t vary much, you’d better get one from the same manufacturer for a perfect match. Sometimes, the differences are all found in the details. 

Anything about replacing a toilet tank may not be as easy as you’d imagine. In this post, I will elaborate on how to find a tank that can fit your toilet bowl, why toilet tanks are not interchangeable, as well as how to replace them on your own. 

These pieces of information would be beneficial and let’s dive in!

Types of toilet tanks

It is important to understand which type of toilet tanks we have before purchasing a new one. While a few of us choose to use a customized toilet, most toilets belong to these three categories we list below.

Gravity toilet tank

The gravity tank is the most common type of tank in America. If you find a lever on the front side of the tank, it is likely a gravity tank. 

There are two holes on the bottom for filling and releasing the water. It takes advantage of the gravity pressure to flush out the waste in the bowl. When you press the lever, it will start to work. 

This type of flushing system has a long history, and you can easily find the replacements in the local hardware and home improvement stores. 

Dual flush toilet tank

As the name suggests, this is a water tank with two flush options – one for solid waste and another for liquid waste. You can find two buttons on the top of the tank for controlling the amount of water used. 

More and more people turn to using it these days to save more water. So you can find many replacements in the local stores and online. 

Pressure-assisted toilet tank

Pressure-assisted toilets are not as famous as the two types I just mentioned. Therefore, it would be harder for you to find compatible parts and tanks. 

This type of toilet tank has an airtight plastic tank inside the tank. When water continues to fill the tank, the air pressure will go up accordingly. When you flush the toilet, it can provide high pressure to wash away the waste quickly. 

Aside from that, many people use the one-piece toilet. In this case, you have to replace the whole unit completely.

How to identify which type of tank you have?

When you want to find a new tank for your old toilet, you should ensure which type of tank you need. If you purchase a tank in another category, it is likely that it wouldn’t be a perfect fit. 

You can find the brand and series number on your toilet tank and then check the information on their official website. Or you can just read the information in the instructional manual. 

Some series numbers are located on the bottom of the tank, so you may need to do a bit of cleanliness to see it. Many tanks are the breeding ground of black mold.

Your best bet is always finding a new tank with the same series number. If the tank has been last for a long time, the model may be discontinued. Then you should consult your manufacturer to see if there are any compatible models available. 

Some tanks are relatively universal, meaning that they can fit an array of toilet bowls. But you can’t decide just with your intuition. Instead, you should check the information provided by the manufacturer.

Can you buy a toilet tank from another manufacturer?

You may find some universal tank models in the same brand, and they can fit your toilet bowl well. However, it is not recommended to get one from another brand even if it looks the same on the outside. 

Different manufacturers often have different designs, meaning that some tiny details can stop the tank from being compatible with your old toilet. Sometimes, it is hard to tell the differences.

So it is better to be safe than sorry. If you aren’t keen on this brand anymore and have to replace the tank, your best bet would be to get a new whole toilet from another brand you prefer.

Are toilet tank bolt sizes standard?

Barring a few unique shapes of toilet tanks, most models use one of two sized bolts: 1/4th inch and 5/16th inch. 

You can find the correct specs on the bolt itself. If it is blurred, don’t worry. You can take one of them to the local store, and I am sure the assistant can figure it out for you.

Or you can measure the diameter of the bolt head and thread length and find a replacement online.

Should you replace the toilet tank?

are toilet tanks interchangeable

Most people who want to know if a toilet tank is universal are planning to get one tank. Nevertheless, it is possible that you can fix the tank effortlessly without having to purchase a new unit. 

The common problem with a tank is that it flushes the toilet automatically every few minutes or hours. This is because the flapper can’t stop the water from releasing into the bowl, and when the tank is emptied, it will start to refill the water again. 

So what you need to do is fix or replace the flapper, which is far less expensive. 

Some customers also found that their toilet tanks produce trickling sounds. It may be because the water is running into the overflow tube. To deal with it, you only need to make some adjustments.

It is critical to understand the causes of your tank problems and make sure replacing a tank is necessary.

How to measure a toilet tank?

For double-checking the compatibility of the toilet tank, you can take some measurements. Usually, you should know the tank’s width, length, and depth. 

Prepare a measuring tape, a notebook, and a pen, and record all the data you need. 

You should also check the sizes of pipes, fixtures, and other parts, which can save you a bunch of money if you don’t need to replace them.

How to replace a toilet tank?

As long as you find a suitable replacement for your tank, it is time to get your hands on how to replace it. You can always seek professional help. Installing it on your own is also possible. 

1. Turn off the water supply and empty the tank. ( The same as we try to install a bidet attachment.)

2. Loosen the bolts and nuts and pull up the broken lid you want to replace.

3. Clean the surface between the tank and bowl.

4. Put the new tank in place. 

5. Place the washer over the bolts and tighten the nuts.

6. Turn on the water supply and test it.

Are toilet tanks interchangeable? conclusion

Toilet tanks are not universal. If you want to find a replacement for your tank, the best way is to get one with the same brand and serial numbers. Some toilets can be compatible with a few different models of tanks, but you should ensure the details with the manufacturer.

Don’t try to get a tank from another brand since there are so many differences in the details even though they look similar. 

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Kevin Chow is an enthusiast of home improvement. He is an engineer and likes to test all the tech gadgets on the market. He starts to use bidet seats after his journey to Japan and he had tried a few brands.