Connecting PVC to PEX | The Best DIY Guide

Connecting PVC TO PEX

Plumbers and DIY enthusiasts alike have found great value in using cross-linked polyethylene (PEX) pipes due to their user-friendly design. These pipes are flexible, enabling them to curve in virtually any direction.

They also come in red and blue colors, making it a breeze to identify hot and cold water lines. The good news is that connecting PVC to PEX is a straightforward task. If you’re aiming to repair or extend your plumbing system, incorporating PEX into your current setup can be done effortlessly with a threaded fitting.

Generally, a fitting has one part that connects to the existing pipe and another that attaches to the PEX pipe. By screwing both parts together, a secure and watertight connection is formed.

PEX pipes bring a touch of simplicity and versatility for both seasoned plumbers and DIY enthusiasts. Effortlessly bending to your will, these pipes connect seamlessly with existing water lines in your home, whether for repairs or fresh installations.

Got PVC pipes already in place? No worries! A diverse array of PEX components ensures you can snap those connections together like a pro, empowering you to tackle your plumbing projects.

Curious about incorporating new PEX into your current water lines? Stay tuned as we unveil the essential fittings and gadgets and their purpose to help you quickly establish those connections.

Embarking on a plumbing repair or expansion journey? Integrating PEX into your current setup is a breeze, all thanks to the trusty threaded fitting. As a rule of thumb, this fitting consists of two parts: one for connecting to your existing pipe, and the other designed to fit the PEX pipe snugly. Joining both halves together through threading results in a connection that is impervious to water.

Required Threaded Fittings

Expansion Fittings involve using a PEX expander tool to stretch the pipe’s diameter to accommodate the fitting. Once the fitting is inserted and the tool is removed, the PEX pipe returns to its original size, resulting in a secure seal around the fitting.

For Compression Fittings, a brass nut and plastic compression ring are first slid over the PEX pipe before the fitting is inserted. A metal sleeve is then inserted, and the nut is tightened to create a seal by compressing the ring around the pipe.

Crimp Fittings require slipping metal rings over the end of the pipe before inserting the fitting. To secure the fitting and ring, a PEX crimping tool is used to tighten the ring around the pipe and fitting, ensuring a tight seal.

Clamp Fittings follow a similar process to crimp fittings, but instead of using a crimping tool, a ratchet clamping tool is used to tighten steel rings on the PEX pipe. The fitting is placed in the pipe’s end, and the ring is compressed over the fitting via a side tab using the clamping tool.

Push-Fit Fittings are the easiest to install, as they do not require any tools or clamping. Simply insert the PEX pipe into one end of the fitting, and it will securely lock into place internally, providing a quick and hassle-free connection between PVC and PEX.

Step-by-Step Guide to Connecting PVC to PEX

Gather the necessary materials and tools:

  • Before starting, make sure you have the following items on hand:
  • PVC pipe
  • PEX pipe
  • Male plastic adapter fitting for PVC
  • Female metal adapter fitting for PEX
  • PVC primer
  • PVC glue
  • Plumber’s tape
  • Pipe cutter or hacksaw (for cutting pipes)
  • Crimping, clamping, or expansion tool (depending on the chosen method)
  • Clean cloth or paper towel

Cut and Prepare the Pipes: Determine the necessary lengths for both the PVC and PEX pipes. Utilizing a pipe cutter or a hacksaw, meticulously trim the pipes to the specified dimensions. Eliminate any burrs or remnants from the severed edges, and cleanse the pipes using a cloth or paper towel.

Attach the Male Plastic Adapter Fitting to the PVC Pipe: Apply the PVC primer to both the fitting and the pipe end, cleaning and slightly softening the surface. Next, spread adhesive on the pipe’s end and the interior of the fitting. Gently slide the fitting onto the PVC pipe and allow it to set.

Attach the Female Metal Adapter Fitting to the PEX Pipe: Based on your preferred technique (crimping, clamping, or expansion), secure the threaded female fitting to the end of the PEX pipe. Adhere to the manufacturer’s guidelines for the particular tool and approach being employed.

Connect The PVC and PEX Pipes: With both pipes now equipped with adapter fittings, it’s time to connect them. Wrap the plumber’s tape around the threaded male fitting on the PVC pipe to ensure a watertight seal. Carefully screw the female fitting on the PEX pipe onto the male fitting on the PVC pipe, tightening it securely.

Inspect and test the connection: Once the connection is complete, visually inspect it for any gaps, misalignments, or other potential issues. Turn on the water supply and check for leaks around the connection. If you notice any leaks, tighten the fittings further or add more plumber’s tape as needed.

The Importance of Connecting PEX to PVC Correctly

Before we dive into the different methods of connecting PEX to PVC, let’s discuss why it’s essential to do so correctly. PEX pipes are commonly used for hot and cold water supply lines, while PVC pipes are typically used for drainage systems. Mixing these two types of pipes in the wrong way can lead to a host of problems. For example:

Chemical incompatibility: PVC pipes contain chemicals that can react with PEX pipes, leading to corrosion, leaks, and contamination of the water supply.

Different expansion rates: PVC pipes expand and contract at a different rate than PEX pipes when exposed to temperature changes. This can lead to stresses that could cause the fittings to loosen, resulting in leaks.

Different strength and durability: PVC pipes are less flexible than PEX pipes, making them more prone to cracks, leaks, and bursting.

That’s why it’s essential to use the proper technique when connecting PEX to PVC pipes.


Connecting PVC to PEX pipes may seem daunting at first, but with the right fittings, tools, and some patience, it’s a task that DIY enthusiasts can tackle with confidence. This comprehensive guide has provided you with the necessary knowledge and steps to achieve a successful connection. With practice and experience, connecting PVC to PEX becomes an easier and more efficient process.

Happy plumbing!

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