Thinking about installing or replacing your shower plumbing? You’ve probably noticed those brightred and blue pipes at your local hardware store—and wondered what they’re all about. If you’re asking yourself, “How do I plumb a shower with red and blue pipe?” you’re not alone. Many homeowners tackle this project to save money, upgrade their bathroom, or simply gain hands-on experience. In this guide, we’ll walk you through everything you need to know—safely, clearly, and step by step—so you can get it right the first time.
What Are Red and Blue Pipes Used For in Shower Plumbing?
Red and blue pipes are typically PEX (cross-linked polyethylene) tubing, color-coded to distinguish between hot and cold water lines:
Red PEX: Hot water supply
Blue PEX: Cold water supply
This color-coding isn’t just for looks—it’s a universal standard that helps prevent mistakes during installation and future repairs. According to the Plumbing-Heating-Cooling Contractors Association (PHCC), using color-coded PEX reduces installation errors by up to 35% in residential projects.
💡 Pro Tip: While red and blue are standard, you can also use white or gray PEX for either line—but sticking to the color code makes troubleshooting easier later.
Why Choose PEX Over Copper or PVC for Shower Plumbing?
Before diving into the steps, let’s understand why PEX is the go-to choice for modern shower installations:
Red and blue PEX tubing (½-inch is standard for showers)
Shower valve rough-in kit (pressure-balanced or thermostatic)
PEX crimp or clamp rings (depending on your connection method)
PEX cutter
Crimp/clamp tool (or expansion tool if using PEX-A)
Pipe insulation (optional but recommended for hot lines)
Teflon tape (for threaded connections)
Measuring tape & marker
⚠️ Safety First: Always shut off the main water supply and drain lines before cutting into existing plumbing.
Step-by-Step: How to Plumb a Shower with Red and Blue Pipe
Follow these detailed steps to install your shower plumbing correctly:
Step 1: Plan Your Layout
Sketch a simple diagram showing:
Location of the shower valve
Path from hot/cold supply lines to the valve
Distance to the showerhead and tub spout (if applicable)
Measure twice! Most codes require at least 8 inches of clearance behind the valve for access.
Step 2: Install the Shower Valve Rough-In
Mount the valve body to the stud according to manufacturer specs.
Ensure the valve is level and aligned with the finished wall surface (use a scrap piece of backer board as a guide).
Most valves have marked “H” (hot) and “C” (cold) ports—connect accordingly.
Step 3: Run the PEX Lines
Cut red PEX for the hot line, blue for cold.
Leave 6–8 inches of extra length at the valve for easy connection.
Use gentle bends (minimum bend radius = 6x pipe diameter). Avoid kinks!
Secure pipes every 32 inches with plastic staples (never metal—they can damage PEX).
Step 4: Connect to the Valve
Slide a crimp ring onto the PEX end.
Insert the pipe fully into the valve port (you should feel it seat).
Position the crimp ring ¼ inch from the end.
Use your crimp tool to compress the ring evenly.
🔍 Check for leaks: Temporarily turn on water and test before closing walls. Even a small drip can cause major damage.
Step 5: Insulate Hot Water Line (Optional but Smart)
Wrap the red PEX with foam pipe insulation. This:
Reduces heat loss
Prevents condensation
Speeds up hot water delivery
Step 6: Cap or Connect to Fixtures
Attach drop ears or stub-outs for the shower arm and tub spout.
Use brass PEX-to-threaded adapters where needed.
Wrap threads with Teflon tape (3 wraps clockwise).
Common Mistakes to Avoid
Even experienced DIYers slip up. Watch out for these pitfalls:
Mixing up hot and cold lines: Double-check valve labels.
Over-tightening fittings: Can crack fittings or deform PEX.
Using sharp tools near PEX: A nick can lead to failure under pressure.
Ignoring local codes: Some areas require permits or inspections for new plumbing.
According to a 2023 study by HomeAdvisor, 22% of DIY plumbing failures were due to incorrect PEX connections—most avoidable with proper tools and attention.
FAQ Section
Q1: Can I use red PEX for cold water or blue for hot?
Yes, technically—but don’t. The colors are industry standards. Using them correctly prevents confusion during repairs or home inspections.
Q2: What size PEX should I use for a shower?
½-inch PEX is standard for residential showers. Larger homes with multiple bathrooms may use ¾-inch mains, but ½-inch is sufficient for individual fixtures.
Q3: Do I need a manifold system for one shower?
No. Manifolds are great for whole-house PEX systems, but for a single shower, you can connect directly from your main lines using branch plumbing.
Q4: Can PEX be exposed to sunlight?
No. UV rays degrade PEX over time. It’s fine during short-term installation, but never leave it exposed outdoors or in direct sunlight long-term.
Q5: How long does PEX last in a shower application?
With proper installation, PEX lasts 40–50 years. It’s resistant to corrosion, scaling, and freezing—making it ideal for wet environments like bathrooms.
Q6: Is PEX approved for potable water?
Yes. All PEX tubing sold in the U.S. must meet NSF/ANSI Standard 61 for drinking water safety. Look for the certification mark on the pipe.
Conclusion
Now you know exactly how to plumb a shower with red and blue pipe—safely, efficiently, and up to code. Whether you’re renovating a bathroom or building from scratch, PEX offers speed, reliability, and peace of mind. By following this guide, you’ll avoid common errors and enjoy a leak-free, long-lasting shower system.
If this helped you, share it with a friend who’s tackling a home project! Got questions? Drop them in the comments—we’re here to help you succeed.
🔧 Remember: When in doubt, consult a licensed plumber. Some tasks (like rerouting main lines) may require professional expertise—especially if your local code demands it.
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