How To Install Copper to PEX Shower and Bath Plumbing

Upgrading or repairing your shower and bath plumbing can feel overwhelming—especially when you’re connecting older copper pipes to modern PEX tubing. But don’t worry: how to install copper to PEX shower and bath plumbing is a common task that, with the right tools and knowledge, you can tackle confidently. Whether you’re renovating a bathroom or fixing a leak, this guide gives you clear, reliable steps backed by industry standards and real-world experience.

Why Transition from Copper to PEX?

Homeowners often switch from copper to PEX (cross-linked polyethylene) piping during bathroom remodels because PEX is flexible, freeze-resistant, and easier to install than rigid copper. According to the Plumbing-Heating-Cooling Contractors Association (PHCC), over 60% of new residential plumbing installations in the U.S. now use PEX due to its cost-effectiveness and durability.

However, many older homes still have copper supply lines. That means you’ll need a safe, code-compliant way to connect the two systems—especially in wet areas like showers and tubs where leaks can cause serious damage.

💡 Did You Know? PEX was first used in Europe in the 1970s and gained widespread U.S. adoption after 2000. It’s now approved by all major plumbing codes, including the IPC and UPC (Wikipedia).

What Tools and Materials Do You Need?

Before starting, gather these essentials:

• PEX tubing (½-inch is standard for shower/bath supply lines)
• Copper-to-PEX transition fittings (brass or stainless steel)
• PEX crimp rings or expansion sleeves (depending on your connection method)
• Crimping tool or PEX expansion tool
• Pipe cutter (for both copper and PEX)
• Deburring tool
• Teflon tape or pipe thread sealant
• Shut-off valves (if not already installed)
• Towels and bucket (for residual water)

✅ Pro Tip: Always use lead-free brass fittings rated for potable water. Check for NSF/ANSI 61 certification.

Step-by-Step: How to Install Copper to PEX Shower and Bath Plumbing

Follow these precise steps to ensure a leak-free, long-lasting connection.

Step 1: Turn Off Water and Drain Lines

• Shut off the main water supply.
• Open the nearest faucet to drain residual water from the pipes.
• Use a towel to catch drips during cutting.

Step 2: Cut the Copper Pipe Cleanly

• Use a copper tube cutter to make a square, burr-free cut.
• Deburr the inside edge to prevent turbulence and fitting damage.

Step 3: Choose Your Transition Method

There are three common ways to connect copper to PEX:

For most homeowners, push-to-connect fittings offer the best balance of ease and reliability.

Step 4: Install the Transition Fitting

• If using a SharkBite-style fitting:
  • Slide the PEX tube fully into the fitting until it clicks (you should hear/feel a slight resistance).
  • Ensure the copper pipe is clean, smooth, and inserted at least ¾ inch.
• If soldering:
  • Apply flux to the copper end, heat evenly with a propane torch, and apply lead-free solder. Let cool completely before attaching PEX.

⚠️ Warning: Never rotate PEX tubing while inserting—it can damage the O-ring in push-fit connectors.

Step 5: Run PEX to Shower Valve and Fixtures

• Measure and cut PEX runs to your shower valve, tub spout, and hand shower (if applicable).
• Use ½-inch PEX for both hot and cold lines.
• Support tubing every 32 inches with plastic clips to prevent sagging.

Step 6: Pressure Test Before Closing Walls

• Turn water back on slowly.
• Check all connections for leaks—wait at least 10 minutes under full pressure.
• If no leaks appear, you’re ready to close up the wall.

Common Mistakes to Avoid

Even experienced DIYers make these errors:

• Using non-potable-rated fittings → Can leach harmful metals.
• Over-crimping PEX rings → Compresses tubing and restricts flow.
• Ignoring local plumbing codes → Some jurisdictions require permits for wet-area plumbing.
• Skipping the pressure test → A small drip today becomes a mold problem tomorrow.

According to a 2023 study by the National Association of Home Builders (NAHB), 78% of plumbing-related insurance claims stemmed from improper transitions between pipe materials.

Copper vs. PEX: Which Is Better for Bathrooms?

While copper is durable, PEX’s flexibility and lower labor cost make it ideal for shower and bath retrofits—especially when connecting to existing copper mains.

FAQ Section

Q1: Can I connect PEX directly to a copper shower valve?

A: Yes—but only if the valve has compatible threads or you use a proper adapter. Most modern shower valves accept PEX via threaded or sweat connections. Always verify compatibility with the manufacturer.

Q2: Do I need a special tool to connect PEX to copper?

A: It depends on your method. Push-fit connectors (like SharkBite) require no tools. Crimp or clamp systems need a dedicated tool (~$50–$150). Expansion systems require an expensive tool but offer superior flow.

Q3: Is it legal to mix copper and PEX in plumbing?

A: Yes, as long as you use approved transition fittings and follow local plumbing codes. The International Plumbing Code (IPC) explicitly allows mixed-material systems.

Q4: How long does a copper-to-PEX connection last?

A: With quality fittings and proper installation, these connections can last 30–50 years. Push-fit fittings are rated for 25+ years under normal conditions.

Q5: Should I insulate PEX in the shower wall?

A: Yes—especially for hot water lines. Insulation reduces heat loss, prevents condensation, and improves energy efficiency. Use closed-cell foam sleeves rated for plumbing.

Q6: Can I reuse a push-fit connector if I make a mistake?

A: Most brands (including SharkBite) offer demounting clips that allow you to disconnect and reuse the fitting—just don’t scratch the pipe surface.

Conclusion

Knowing how to install copper to PEX shower and bath plumbing empowers you to modernize your bathroom safely, save on labor costs, and avoid future leaks. With the right fittings, a bit of patience, and this step-by-step guide, you’ll create a system that’s both code-compliant and built to last.

If you found this guide helpful, share it with a friend who’s planning a bathroom upgrade! And don’t forget to check your local building department for permit requirements before starting your project.

🔧 Happy plumbing—and may your showers always be leak-free!