I’ve been doing some DIY and was looking at replacing some pipes that have a minor leak. While learning how to do it, I wanted to know how to connect a copper pipe to a PVC pipe. Based on the recommendation of very experienced plumbers, here’s what I found.
There are 3 methods for connecting PVC pipe to copper pipe:
- Copper to PVC compression-fittings
- Push-fit fittings, also known as Sharkbite fittings
- Copper female threaded fitting connected to a male PVC threaded fitting wrapped in Teflon tape.
However, there are a few things to keep in mind so that you get a 100% watertight seal that lasts as long as it should. Below, I will explain everything you need to know about how to connect PVC pipe to copper pipe, as well as, the different fittings and when they should be used.
Best Fittings to Connect PVC to Copper Pipe
Since there are now 3 major fittings to connect PVC to copper pipe, you may be wondering which is the best type to use and why. Here’s what plumbers recommend:
As a general rule, compression fittings are the best fittings to use to connect PVC to copper pipe. A soldered fitting is also a good option. However, it requires the use of an open flame which can be dangerous for DIYers. Push-fit fittings aren’t generally recommended for most PVC to copper pipe connections.
Here’s a table that shows the best copper to PVC fitting with summary of why
| Best to worst PVC to copper fitting | Reason |
|---|---|
| Compression | Lasts a long time, easy to install, doesn’t require an open flame |
| Solder | Lasts a long time, easy to install – but does require a bit of skill and is less safe to install than a compression fitting |
| Pushfit – also called shark bite | Generally only for short term use like supply lines for appliances. |
Certain appliances will have a warranty on them for around 10 to 30 years. And because of that, you can replace all of the fittings when you replace the appliance. Therefore, push-fit fittings can be a good option for certain appliances like these.
For supply lines, though – the water from the mains into the house – you want to use a longer-lasting fitting such as a compression fitting or solder fitting.
Below, I will explain how to connect a PVC pipe to a copper pipe for compression fitting and solder fitting.
How do you connect copper pipes to compression fittings?
Compression fittings are the best fitting to connect copper pipes to PVC pipes, and are also good for connecting copper to copper. So, then how do you connect a compression fitting, exactly?
To connect a copper pipe to a compression fitting, first, slide the nut that comes with the fitting over the end of the pipe you’re attaching the fitting too. Then, slide the ‘olive’ over the same end. After that, put the fitting on it, hand tighten the nut to the fitting, and tighten it with a spanner.
You don’t need to tighten it as hard as you can, but you need to use a good amount of force. Tighten as tight as you would a normal screw to the point where you need to use quite a bit of force to loosen it again.
When you tighten the nut using an adjustable spanner it will crimp the olive to the pipe. And creates a watertight seal between the olive and the nut.
If you’ve ever attached a hose attachment to your garden hose for watering your yard or washing your car, a compression fitting works almost the same.
Here’s short video that shows what a compression fitting looks like and how it attaches to the pipe:
There are a few considerations when using a compression fitting so that it stands the test of time. They are:
Always Use a Liner on the PVC Pipe End
A liner is a small attachment that slots inside the end of a PVC pipe. It increases the strength of the end of the pipe so that it doesn’t crack. If you don’t, later down the road, it can lead to leaks.
A liner is very inexpensive and costs around 50 cents. However, they dramatically increase the life of your pipes, and an expert plumber recommends always using one on the PVC end of a pipe you’re attaching a compression fitting to.
Use PTFE Tape on the Olive
PTFE tape, often called plumbers tape, is a special type of tape that improves the seal between plumbing joints. It’s recommended to apply around 3 layers of PTFE tape to the olive. You start by attaching one end of the tape to the olive, wrapping it around 3 times, and then breaking it off.
An experienced plumber had mentioned that they had had a few callbacks to previous jobs they did because of leaks when they didn’t use PTFE tape. However, when they used PTFE tape, they never had any issues and thoroughly recommends it. It’s also widely used amongst plumbers.
But, it does add a bit of time to installing the fitting. The general procedure is to attach the fitting and then undo it to apply the PTFE tape.
Once you attach the fitting, the olive will be crimped to the end of the pipe, and you can then apply PTFE tape to it. After you apply the tape, you put the other part of the fitting over it and screw it tight again – by hand and then with a spanner.
How a Compression Fitting Compares to a Solder Fitting
With a solder fitting you solder it to the copper pipe end, and then glue the PVC pipe end to. The steps to solder the fitting to the copper pipe are are:
- Apply flux to the end of the pipe
- Thread the copper fitting over the end of the pipe
- Solder it together
It is a specialist skill; however, it is not that difficult to master. Here’s an excellent video I found that explains the ins and outs of soldering copper fittings and exactly how to do it:
How To Connect PVC to Copper Pipe Without Welding?
Because welding is a specialist skill, it can be easier to use another way to connect a PVC pipe to a copper pipe. But, what options are there, and how do you do it?
A compression fitting is the best way to connect PVC to the copper pipe without welding. Another option is a push-fit fitting, also called a shark bite fitting. However, they have a shorter life than a compression fitting, and therefore push-fit fittings aren’t recommended for long-term use, such as supply lines and wastewater lines.
Attaching a compression fitting or a solder fitting are about the same difficulty once you know how to do them. However, welding requires much more equipment.
