Can I Connect PEX to CPVC? (Connecting PEX to CPVC Guide)

With the cost of professional labor going through the roof, it makes sense to try and DIY. You certainly save money and you learn new skills as well as techniques. The only problem is that you also have to learn what fits together and what doesn’t.

Can I connect PEX to CPVC? It is possible but after spending large sums on the products you need, you also have to send an extraordinary amount on the special tools that are required. There are special fittings that may not need those special tools and you may get a good fit when you are done.

To learn more about connecting CPVC piping to PEX piping just continue to read our article. it has the information you need to know about to get the job done right. The main concern will be making sure there are no leaks.

Connecting PEX To CPVC


The reason this question is being asked is that PEX piping is very flexible, easy to feed through walls, saving on tearing the wall apart to get the pipe in place, and other benefits.

Then, even connecting the different piping materials is easy. There are two fittings that you need. One goes on the end of the PEX pipe and the other goes on the PVC or copper pipe. Once they are on, you just join the two halves together and you have a great connection.

The difficult part will be on the copper or CPVC pipe part. There you may need to use heat or glue to make sure the fitting is secure and water-tight. Then you may need special tools to do that work.

The PEX side of the connection does not need those same tools and the ones you do need depend on the type of fitting you are using. There are 5 different fittings to choose from and the one you choose will dictate the type of tools or materials you will need.

Can PEX Be Glued To CPVC?

No, this is not a possibility. The reason for this is probably found in the ingredients and the way PEX piping is made. Nor can you glue to PEX pipe ends together to make the perfect fit.

The only way to use this new piping material is to use the correct fitting for the connection you are trying to make. Those fittings come in either metal or plastic construction materials so you need to decide which one will last the longest for the purpose you have in mind.

If you go with PEX fittings, and not Sharkbite or Sea tech fittings, then you will need to buy the special PEX crimping tool. The cost of that tool runs between $35 and $100. Of course, those two brands of fittings can cost anywhere between $6 and $20 depending on where you shop.

That makes the latter option a lot more attractive as you may not need more than one or two fittings to make your connection. But if you are re-plumbing your pop-up or RV, the PEX pipe with the PEX fitting and crimping tool would be the way to go.

How To Connect PEX To CPVC Pipe


This is not that difficult on the PEX side of the situation. There are different fittings that you can use like the expansion version. There is a PEX expander tool that helps you make the PEX pipe opening large enough to put the fitting inside.

Then because the PEX pipe has a memory, it shrinks back to its normal size and creates a watertight seal. The other side of the connection may not be as easy and with copper, you may need to use solder to get the fitting to be watertight and secure.

When attaching the PEX piping to the CPVC piping, you need the male fitting to be on the CPVC side of the equation and the female on the PEX side. The reverse ends up stripping the threads and ruining the fittings.

Once you have that sorted out, you use the standard CPVC method of connecting the fittings to the CPVC pipe. You use CPVC primer on both the pipe and the fitting, then the glue. That should do the trick.

The key is to buy the right size of fitting and one of the 5 options that should work for your connection project.

Can You Use PVC Fittings With PEX Pipe?

If you are trying for a straight connection, then the answer would be no, you can’t. The reason for that answer is that the PEX sizing chart and the PVC sizing chart are not the same. The PVC side of the plumbing industry is larger than the PEX side.

The tried and true way of connecting the two pipes is by using the proper adapters that will fit with each construction material. The PEX side, like for CPVC, has to be the female one while the PVC side will have to be the male side.

After you place the fittings on the different pipes, use a little Teflon tape and thread the two connections together. If you did not know, there is a Sharkbite connection that will now work between PEX and PVC piping. This is supposed to be a recent development so it is not known how well known this upgrade is.

This option may be a better fit than trying to connect two different-sized fittings together. If you are still unsure, you should check with some plumbing experts but you may get 4 different opinions about PEX before being told how to make a good connection.

Can You Use PVC Glue on PEX Pipe?


The last word we heard was that this was an impossible task to try to perform. The glues on the market today don't seem to work with PEX construction materials. You should talk to some experts to see what options you have available.

With that said, we have read that there are glues that will join these two materials together but the information did not come from an authoritative site. Take the information with a grain of salt and double-check.

Or some reason, the makers of PEX made the material impervious to glues as you cannot even use this adhesive to join two PEX lines together. You will have to use one of the 5 fittings that are made for PEX material and the other piping material you are using to make the connection.

Those 5 fittings are expansion, crimping, compression, clamp, and push-fit. The one you use is up to the project at hand. But these fittings will direct you to different tools. there is no one size fits all tool you can buy and use for all fitting options.

PEX Pipe Glue

There is no such thing as PEX glue. This piping material cannot be glued together nor glued to any other material using special glues made for those alternative options. There is only a couple of connection options you have to choose from.

The first is is using the Sharkbite or the Sea Tech connection methods. These methods do not need any glue or sealer. You just make sure you have a clean edge, no burrs, and push the pipe into the Sharkbite fitting. It may take half a twist to get done.

The other connection option would be to pick one of the 5 fittings we just mentioned and use them correctly. If you are not sure which one to use, talk to the experts where PEX fittings and materials are sold. They will get you sorted out and make sure you have the right parts.

Unless a glue has been invented in the last few years, it is not being talked about by anyone or sold by any of the many affiliate marketers that have taken over marketing recently. It would be good news if one was invented.

How To Connect PVC To PEX


1: Make sure the edges of both pipes are clean, straight and there are no burrs left over. That may take using some sandpaper to clean up after cutting the pipes.

2: On the PVC side of the connection, you need to use PVC primer and adhesive. Spread it over the interior of the PVC pipe and the fitting you are using. Once that is done, push the fitting into the PVC opening and hold it together for about 1 minute.

3: Depending on the fitting you chose to use, push the fitting into the PEX pipe and use the crimping tool for the crimp fitting and other tools for the alternatives. make sure the PVC side has the male end and the PEX side has the female end.

4: Add some Teflon tape to the fitting’s threads and simply connect the two halves.

5: You can add some sealant tape to make sure the connection is watertight.

6: Test your connection to make sure there are no leaks. if there are none then you are done. This is not a hard project to complete and is a lot easier than working with copper piping.

PVC To PEX Transition Fitting

The challenge to making this connection is that PVC pipe and its fittings are larger than the PEX piping and its fittings. The first thing you need to do is find compatible fittings that will work well together and create that watertight seal you want.

Your plumbing supply or hardware store should have all the right sizes to match the pipe sizes you are using. One thing is for sure, you will need threaded adapters to make this connection work.

The transition fitting you should look for is the PEX x FNPT and it will work with any fitting style you are using. The key is to make sure the fittings are on the right sides of the two pipes. You do not want to go out and buy another transition fitting.

Placing the two halves on the wrong side should strip the threads making them useless. If in doubt always ask the experts to show you how it should go and what materials you need to seal the transition fitting in place.

Making the connection is a lot simpler than it was in your grandfather’s day.

Will CPVC Connect To PVC?


This is an interesting question because normally, these two pipe options are not used together. They have different purposes so they are not used in the same applications. Plus, they are made differently allowing the CPVC to withstand temperatures up to 200 degrees F. PVC starts degrading at 140 degrees F.

Then CPVC is made in two different sizes. The NPS size will fit PVC pipes as that material is made in the same NPS size. The CTS variation fits the copper pipes sizing. When putting the two materials together you cannot use regular PVC primer and glue.

You have to move up to a solvent glue because CPVC is stronger than PVC and the other glues won’t hold it. You will also need a solvent primer to create the strong bound just like you would with regular PVC glue.

You can join the two piping materials together if you have the right adhesive to work with. Like working with PVC glue, you have to be extra careful when working with solvent cement.

Some Final Words

When you are making new water connections, it is best to go with the best materials. PEX piping uses fewer connections than PVC, copper, and other pipe materials. Plus it is easier to work with.

The flexibility of the PEX pipe allows you to cut fewer holes in your walls to install it. Less work is always a good thing especially when you are still getting quality results and longevity out of the new pipe.

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