PVC Union Vs. Coupling: What Are The Major Differences?

Plumbers often face confusion when deciding between a PVC union vs coupling. While some may assume that these products are interchangeable, there are in fact significant differences between the two.

PVC unions are designed to enable easy removal of a section of pipe without needing to cut it, while PVC couplings are used to join two pieces of pipe together permanently. Therefore, it’s crucial for plumbers to carefully evaluate their requirements and select the appropriate product based on their specific needs.

PVC Union Vs. Coupling: What Are The Major Differences?

Yes, both a union and a coupling are used to connect pipes, but they are not all that similar.

Besides the type of finish and connections given, there is also a major difference in the type of problem that the processes can fix.

So without further delay, let’s get into the article.

What is PVC Union?

PVC Union Vs. Coupling: What Are The Major Differences?

PVC unions are sort of like connectors that are designed to bring together two pipes. It is a part that helps make the connection without having to use any glue or sealant.

It is a connector that is made of PVC and is used quite a lot in construction work.

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Advantages and Disadvantages Of PVC Union

One of the main advantages of using a PVC pipe union is that – the joints can be put together and taken apart very easily. You don’t have to invest in any specialized tools.

The only disadvantage of using this very useful PVC union is that – it is not much of a high-quality product. PVC unions can be quite brittle and can therefore crack and break very easily.

This is why this union needs to be handled quite carefully when working. It also has to be taken care of, especially if used in cold weather.

A PVC coupler Is one of the most inexpensive and basic accessories in plumbing. It is a part that is quite short in construction. The unit is used to connect threaded pipe, or sometimes to adjust tubing thickness. If used properly, a PVC coupler can also come in handy when fixing leaks.

These are an accessory that is used quite widely for their versatility. You will see a PVC coupling be used in petroleum gas, chemical, and surely in the water industry. Even pharmaceuticals use PVC coupling at times.

What is PVC Coupling?

PVC Union Vs. Coupling: What Are The Major Differences?

PVC coupling is a product that is also used for connecting pipes. A key attribute of PVC coupling is that it gives you a more prolonged or permanent type of solution. There are a lot of different kinds of PVC threaded coupling available in the market. Here are a few examples of the common ones.

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1. Half Couplings

A half-coupling is a unit that is half the size. It usually has a socket on one side of its construction. A half coupling can be both- a threaded or a socket type.

The unit is usually welded directly onto a large bore pipe to make any kind of branch connection. Because it only threads on one side, the other end should always be welded with a bevel or plain end.

2. Full Couplings

A full-sized coupling is used for connecting smaller-sized boar pipes. Usually, the unit is used to connect swage to nipple or pipe to pipe. Unlike a half coupling, these have sockets welded connection on both ends. These two can be both threaded or socket and styles.

3. Reducing Coupling

A reducing pipe coupling has the same type of connection on both of its ends. But, both ends are not the same size. Usually, one side is smaller than the other, hence the name-reducing coupling.

This type of pipe coupling is used to extend an already existing PVC fitting.

4. Internal And External Couplings

An internal pipe coupling is installed inside a PVC pipe. It leaves a rather smooth finish.
External couplings are connected either on top or over a PVC pipe. You can see a connection made with external couplings.

5. Compression Coupling

Compression couplings are also referred to as tees. These are mostly used for joining tubes and PVC pipes that are already installed.

A compression coupling consists of a compression seat, compression ring, and a compression nut. These are very easy to install and are the prime choice for making any underground connections.

When it comes to PVC compression coupling vs union, people prefer to go for compression coupling if there is any underground or permanent joint needed. Union is not preferred for connections that are made underground.

6. Repair Coupling

A repair coupling is also very easy to install. It is made to not have any internal stops. Therefore, the unit can be slipped into tight locations quite easily.

A repair or sleep coupling is a very versatile and useful tool that can take on the task of an extra pipe and two couplings together.

Advantages Of PVC Coupling

People mainly gravitate toward using coupling in PVC plumbing because it can provide a more permanent connection. They can be used in a lot of different ways because of the variety that they offer.

Not to mention, the unit is also very easy to install.

Disadvantages Of PVC Coupling

Pvc couplings provide a more permanent connection. Therefore, they are very hard to reassemble or take apart once they have been installed.

Therefore, a coupling should only be installed if you are 100% sure about the necessity of its presence.

Comparison: PVC Coupling VS Union

PVC Union Vs. Coupling: What Are The Major Differences?

Now that we have a clear idea about PVC union and pipe coupling, it is now time to take a look at the differences between the two.

1. Usage

A PVC Union is used when a temporary pipe connection is needed.
On the other hand, the coupling is more of a permanent solution. It can be used to join together pipes or a pipe to a swedge. As an example- compression coupling is used for underground connections.

It must also be stated that couplers are a lot more versatile than unions. There are a lot of different kinds of couplers available in the market that can be a solution to many different problems.

2. Easy Installation

Both products are relatively easy to install.

A coupling uses a simple metal clamp system that does not require any additional items in the toolbox.

Similarly, a PVC union is also quite simple to set up.

3. Cost

When it comes to cost, a PVC union is a more budget-friendly option. Depending on the kind of coupler you are buying, you might have to pay a bit more compared to the union.

4. Design

A coupler usually has very leak-proof technology. They can give you a very rigid joint that usually leaves no room for leakage. It is also much lighter and therefore easy to transport from one place to another.

Unions are non-conductive, rust-resistant, and very lightweight products as well. Similar to a coupler, a PVC union is also quite easy to carry around.


1. Should You Choose A Union Or A Coupling If You Plan On Replacing The Joint?

A union is a joint that can be assembled and disassembled quite easily. Therefore, it is typically used for maintenance or replacement jobs.

On the other hand, a coupling is for a more permanent joint.

That is why, if you are planning on replacement- a coupler should be your choice.

2. How Durable Is A PVC Compression Coupling?

Once installed accurately, a PVC compression coupler can last approximately 100 years!

3. Do PVC Unions Follow A Direction Of Flow?

No, PVC unions are generally non-directional. The position in which you are to assemble the unit will depend on your ease of access and need for disassembly.

4. How Much Should A PVC Union Be Tightened?

After applying the sealant, you need to attach the male thread to the female thread and tighten the joint by hand. After tightening it with your hand, you can use a wrench to tighten it a bit further and that’s it.

It is not advisable to over-tighten the PVC union joint.

Final Words

Now that you know the key differences between a PVC union vs coupling, you should be able to choose your plumbing needs quite easily.

Always remember, that a PVC Union is a temporary solution, while a coupler is a more prominent one. There are a lot of different kinds of couplers available in the market as well, so make sure you understand which type your plumbing system needs.

Both these units are quite easy to install and can be set up at home if you have the proper tools!

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