Your Guide to Pipe Fittings at SUPPLY.com

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As a plumbing supply company, one of our most popular products at SUPPLY.com is pipe fittings. Fittings are the small pieces that join pipes together, so they’re very important. There are many types of fittings, which don’t all have distinct visual features to the untrained eye, so we wrote this guide to help break down the various categories and how they’re used.

Main Types of Pipe Fittings

The first thing you need to know is which plumbing pipe fittings are out there and what their purpose is. The top categories are listed and briefly described below. Remember, these are not the only plumbing fittings available, but some of the key ones you’ll come across.

tee fitting plumbing

Tee Fittings

Tee fittings are used to join three pipes. They are named for their “T” shape with one inlet and two outlets, with one outlet at a 90° angle. This allows for connecting a horizontal pipe to a vertical one.

elbow pipe fitting

Elbow Fittings

Like a tee fitting, an elbow fitting also allows the direction of the water flow to go in another direction. A regular elbow has two female connections on each end to connect two male pipes. A street elbow has a female and a male connection and can therefore connect directly to other fittings.

coupling pipe fitting

Coupling Fittings

Couplings cover two pipes to connect them securely together. A coupling is a small piece of pipe that can be soldered to the pipe. Both sides are female (keep in mind these terms are American – other places like the UK use slightly different nomenclature). An adapter is a coupling with two ends that use separate joining methods.

DWV Fittings

Drain, waste, and vent. DWV fittings attach to DWV pipes, which are used for the above purposes, and shouldn’t be used for anything else involving too much pressure. The smoothness and shape of DWV fittings are designed to facilitate flow and decrease blockages. A DWV fitting can be shaped like the other fitting types mentioned – for example, you can find a DWV elbow or tee.

push fit fitting

Push-to-Fit Fittings

Also known as push-to-connect fittings, push-to-fit fittings are used the way their name might lead you to think – they snap easily into place and don’t require soldering. They’re known for making installation easier, and have a reputation for helping homeowners. Like DWV fittings, push fittings are a type that you can find for different uses – adapters, couplings, etc.

crimp pipe fitting

Crimp Fittings

Crimp fittings involve a fitting situated between two pipes. A metal ring is then placed around the outside of the pipes, and a crimping tool is used to press it together firmly.

nipple pipe fitting

Nipple Fittings

Nipple fittings are male-threaded at the end and are used to connect to female fittings. Determine the type of nipple you need based on connection size and nipple length.

union pipe fitting

Union Fittings

Union fittings have a male and female end and connect two similar pipes. The middle of the fitting is tightened over the two pipes to keep them secured together. These are different from couplings in that they are easier to take on and off to rearrange.

How to Shop Fittings at SUPPLY.com

When you go the Fittings page at SUPPLY.com, you won’t see the top fittings categories laid out the way we listed them above. We chose instead to categorize by the specific way that our plumbers tend to shop, mainly by material. Below is the best way to navigate.

From the homepage, go to the Plumbing tab in the header and go to fittings. Within this page you’ll find over 35 categories divided between fittings and nipples, with labels like “Copper Fittings,” “PVC DWV Fittings,” “PEX Crimp Fittings,” etc.

supply.com fittings and nipples

Most of the categories are split by material, though some are split further by type, like DWV (see image above). The specific fittings you’re looking for are within the category; for example, within “Copper Fittings,” you’ll find Elbows of various sizes, tees, adapters, couplings, unions, caps, flanges, bushings, p-traps, returns, and stub-outs.

supply.com fittings and nipples

Within the category, you can also shop by connection size. Looking at the Copper Fittings example again, you’ll find sizes from 1/8″ all the way up to 6”. On this page, you can also filter by connection types C x C (copper by copper) and FTG x FTG (fitting by fitting).

Which Fitting to Choose

The type and size of fitting you need really depends on the type of pipe you’re using and the job you need to accomplish. If you’re debating which pipe materials to start with, be sure to check out our article on Copper vs PEX tubing.

If you’re looking for a quick way to connect pipes, SharkBite is known for push fittings, which snap easily into place. You’ll find everything from push elbows to push polybutylene conversion couplings (these are used to connect PVC to other materials).

A popular brand known for copper fittings is Nibco; if you’re looking for a trusted producer, check out Nibco elbows, push fittings, DWV fittings and more.


How do I install a push fitting on a copper pipe?

The push fitting works the same way it does on plastic piping. Simply cut the copper pipe to the length you need, insert a pipe liner, make sure the fitting is clean, then push the fitting in until it’s secured into place.

How do I measure pipe fittings?

For male-threaded pipes, measure the outside diameter of the pipe, divide it in half to find the circumference, then divide the circumference by 3.14159 to find the fitting size. For female-threaded pipes, measure the inside diameter of the pipe, then use a nominal diameter conversion chart to find the fitting size.

Can I connect PEX to PVC?

Yes! One way to do so is to find a threaded adapter fitting that will work for both. You may need to tape and glue around the fitting to keep the different-sized pipes secured. Some SharkBite fittings also work to connect these two types of pipes.

How can I loosen a stuck pipe fitting?

There are several approaches to take. First, use a pipe wrench to try and loosen the fitting. If necessary, apply heat with a heat gun to try and soften the fitting, or use an oil to set it free. When all else fails, use a saw to carefully cut the fitting out without cutting the pipe.

How are your fittings packaged?

You can buy fittings individually at SUPPLY.com, but due to their size it’s typically worth it to buy in bulk to avoid paying more for shipping than the cost of an individual fittings. Copper elbows, for example, are usually sold in quantities of 50.

Have a question about plumbing fittings? Give our product experts a call at 877-781-3114!