PVC Fittings Guide


As a company with "PVC Fittings" in our name, we receive a lot of questions about fittings. These questions often have to do with pipe fittings sizes and dimensions, which makes sense because those topics can be confusing! Other questions are about the fittings themselves and what they are meant for. Compatibility and general pipe fitting knowledge can be overwhelming to someone who is new to the world of PVC! If you are trying to expand your PVC knowledge, you can use this blog post as a pipe fitting study guide! This pipe fittings guide will outline all the major types of PVC fittings as well as how and why to use them. This is a long post, so you can use the "Contents" section to navigate it!


>Pipe Fittings Sizes>PVC End Types and Adhesives
>Furniture Grade Fittings Vs. Regular Fittings
>PVC Fittings - Descriptions and Applications
---->Couplings and Unions
---->Caps and Plugs
---->Adapters (Female and Male)


Pipe Fittings Sizes

As mentioned in a previous blog post about PVC pipe outer diameter, PVC pipe and fittings use a nominal system for standard sizing. This is so all parts with the same size in their name will be compatible with each other. All 1" fittings will fit on 1" pipe, for example. That seems pretty straightforward, right? Well here's the confusing part: the outer diameter (OD) of PVC pipe is greater than the size in its name. That means that 1" PVC pipe will have an OD that is greater than 1", and a 1" PVC fitting will have an even larger OD than the pipe.

The most important thing when working with PVC pipe and fittings is the nominal size. A 1" fitting will fit on a 1" pipe, regardless of whether either one is schedule 40 or 80. So, while a 1" socket fitting has an opening wider than 1" across, it will fit on a 1" pipe because the OD of that pipe is also greater than 1".

There may come a time when you want to use a PVC fitting with non-PVC pipe. The nominal size, in this case, is not as important as the OD of the pipe you are using. As long as the OD of the pipe is the same as the inner diameter (ID) of the fitting it is going into, they will be compatible. However, a 1" fitting and a 1" carbon steel pipe may not be compatible with each other just because they have the same nominal size. Be sure to do your research before spending money on parts that may not be compatible with each other!

Click here for more information on PVC outer diameter.

Flange TypesPVC End Types and Adhesives

Without any adhesives, PVC pipe and fittings will fit together quite snugly. They will not, however, be watertight. If you are going to have any fluids passing through your pipe, you will want to ensure that there will be no leaks. There are several different ways to do this, and the method you choose will depend on what you are connecting.

PVC pipe itself does not usually have threaded ends. This is just one reason that most PVC fittings have slip ends. "Slip" in PVC does not mean the connection will be slippery, but rather that the fitting will slip right over the pipe. When putting pipe into a slip fitting, the connection may seem tight, but to transport any liquid media, it will need to be sealed. PVC cement seals pipe through a chemical reaction that bonds the plastic of one part to another. For a guaranteed seal on a slip fitting, you will need both PVC primer and PVC cement. The primer softens the inside of the fitting, preparing it to bond, while the cement keeps the two pieces stuck together tight.

Threaded fittings need to be sealed differently. The main reason people use threaded parts is so that they can be taken apart if necessary. PVC cement bonds pipe together, so if it is used on threaded joints, it will make a seal, but the threads will become useless. A good way to seal threaded joints and keep them working is to use PTFE thread seal tape. Just wrap it around the male threads a few times and it will keep the connection sealed and lubricated. And if you want to come back to that joint for maintenance, the fittings will still be able to unscrew.

Want to know about all the different PVC end types and connections? Click here for more information on PVC end types.

Furniture Grade Fittings vs. Regular Fittings

Often our customers ask us, "What is the difference between furniture grade fittings and regular fittings?" The answer is pretty simple: our furniture grade fittings have no manufacturer printing or bar codes. They are clean white or black with nothing printed on them. This makes them great for applications where the pipe will be visible, whether or not it is actually for furniture. The sizes are the same as regular fitting sizes. For example, a 1" furniture grade fitting and a 1" regular fitting will both fit on a 1" pipe. Also, they are just as durable as the rest of our PVC fittings.

Click here for more information on our furniture grade pipe and fittings.

PVC Fittings - Descriptions and Applications

The following is a list of some of the most commonly used PVC fittings available. Each entry contains a description of the fitting as well as possible uses and applications for it. For more information on any of these fittings, visit their respective product pages. It's important to remember that each fitting has a countless amount of iterations and uses, so keep that in mind when shopping for fittings.


PVC tees are a fitting with three ends; two in a straight line and one on the side at a 90-degree angle. Tees allow a line to be split into two separate lines with a 90-degree connection. Also, tees can connect two lines into one main line. They are also often used for PVC structures. Tees are an extremely versatile fitting that are some of the most widely used parts in plumbing. Most tees have slip socket ends, but threaded versions are available.


If you need your piping system to get turn or get around something in the way, you will need to bend your pipeline around with PVC elbows. Elbows are most commonly available in 90-degree angles and 45-degree angles, so your pipeline can be directed however you want it. Side elbows are a slightly different piece that are commonly used as corners in projects such as canopies, tents, displays, and boxes. They have three ends instead of two. Most elbows have slip socket ends, but threaded versions are available.


Crosses are a slightly less common type of fitting that join four pipe sections. They have four slip connections (S x S x S x S) that meet at 90-degree angles, forming a "plus" shape. PVC cross fittings are usually used when building framework out of PVC pipe. Crosses can add a great deal of structural integrity to a framework. They can also be used to divide fluid flow in different directions.

Couplings and Unions

Couplings are one of the most simple (and inexpensive) types of PVC fittings. They are a small part that connects or "couples" one part to another, usually permanently. They can connect pipe to pipe and pipe to fitting. Some of them even reduce so you can connect a small pipe to a large pipe or vice versa. Couplings are available with slip or female-threaded ends, depending on what you need them for.

Unions, like couplings, connect things, but they are a not-as-permanent solution that can be easily taken apart. PVC unions are often used in building temporary structures, such as tent supports, and can be taken apart when the structure is no longer needed. They feature a ring in the center that separates the two ends from each other, allowing for easy deconstruction and maintenance.

Caps and Plugs

Caps have a very simple job: stop the flow. They are put on the end of a pipeline that does not need to be connected to another pipe. They can stop a pipeline that you plan on expanding later or give you easy access to a system when needed. They can also add a finished look to pipe in PVC building projects. Caps go around or outside the pipe, so they can have either a socket or female-threaded end.

Plugs are like caps, but instead of stopping the flow in a pipe, they stop the flow in a fitting. Because of this, plugs go inside the fitting. This means they either have a spigot or male-threaded end.

Adapters (Female and Male)

Adapters, sometimes called reducing couplings, are a versatile fitting. These fittings are designed to change the end type of a pipe, allowing it to connect to fittings and pipes of many sizes. They can have threaded or slip socket ends to connect to an endless variety of pipes and fittings. Adapters can be either male- or female-threaded, as well as socket or spigot.


Bushings are a lot like adapters, but with a focus on connecting pipes of different diameters by reducing the fitting. (Bushings cannot reduce pipe.) Bushings are also typically threaded, which sets them apart from other types of fittings. This allows for different kinds of connections and makes maintenance and pipeline customization easier. Bushings are often seen in landscaping and aquaculture applications because they work better with water than metal fittings that may rust.


There are some situations in which two female ends in a PVC system need to be connected. The fitting for this job is a nipple. A nipple is a fitting with two male-threaded ends. Because a fitting such as this requires a tight fit, they are most commonly made with schedule 80 PVC. They are still compatible with schedule 40 parts, however.


Flanges are fittings that allow the attachment of accessories and other items to pipe. They can also increase the strength of pipe. The most common type of flange is found at the base of a toilet. Flanges are a disc-like fitting that create a tight seal by pressing two surfaces together with bolts, clamps, edges, or a compressive force. Most flanges, however, use bolts to join the two surfaces together. PVC flanges are available with slip or threaded ends. Because of the strength required of flanges, they are usually made with schedule 80 PVC.


These are just a handful of the more popular PVC fittings. If you continue to learn about PVC pipe and fittings, you will stumble upon many other types of fittings and different varieties of the ones covered here.