Thinking about upgrading your bathroom with a new shower—but worried about the plumbing? You’re not alone. Many homeowners hesitate to tackle how to install plumbing for shower in an existing bathroom because they assume it’s too complex or expensive. The good news? With careful planning, basic tools, and this clear guide, you can do it yourself—or at least understand the process well enough to hire the right pro. Let’s walk through everything you need to know.
Is It Possible to Add a Shower to an Existing Bathroom?
Yes—absolutely. As long as your bathroom has access to water supply lines and a drain system (which most do), you can retrofit a shower into an existing space. According to the National Association of Home Builders (NAHB), over 68% of bathroom renovations in 2024 included adding or upgrading showers, often in powder rooms or older homes that originally had only bathtubs.
The key is working with your current layout—not against it. Whether you’re converting a tub to a shower or installing one in a half-bath, success depends on three things:
Water supply access
Drain line proximity
Proper venting
💡 Pro Tip: Before cutting into walls, use a stud finder and pipe detector to avoid hitting electrical wires or existing plumbing.
What Tools and Materials Do You Need?
Having the right gear makes the job faster and safer. Here’s a checklist:
Essential Tools:
Pipe cutter or hacksaw
Adjustable wrench
Tubing cutter (for PEX)
Drill with hole saw bits
Level
Tape measure
Plumber’s putty & Teflon tape
Common Materials:
PEX or copper piping (½-inch diameter)
Shower valve (pressure-balanced or thermostatic)
Shower arm and flange
Drain assembly (with overflow if needed)
Waterproofing membrane (e.g., Schluter-Kerdi or RedGard)
Shower pan or base (if not using a custom tile base)
⚠️ Note: Local building codes vary. Always check with your municipality before starting. Most U.S. jurisdictions require permits for plumbing modifications.
Step-by-Step Guide: How to Install Plumbing for Shower in an Existing Bathroom
Step 1: Turn Off Water Supply & Plan Your Layout
Shut off the main water valve. Open faucets to drain residual pressure. Sketch your shower location, noting where hot/cold lines and the drain will run. Ideal placement aligns with existing plumbing stacks to minimize wall demolition.
Step 2: Cut Access Panels in the Wall
Remove drywall or tile carefully to expose studs. Create a cavity large enough to work—typically 24″ x 24″. Save removed material in case you need patches later.
Step 3: Install the Shower Valve
Mount the rough-in valve between two studs at standard height: 48–52 inches from the floor. Connect it to hot and cold supply lines using:
Copper: Soldered joints (requires torch)
PEX: Crimp or push-fit connectors (easier for DIYers)
Ensure the valve is level and aligned with your future shower handle.
Step 4: Run the Supply Lines
Use ½-inch PEX tubing (recommended for flexibility and freeze resistance). Keep runs as short and straight as possible. Support pipes every 32 inches with clips.
📊 Stat: PEX piping reduces installation time by up to 40% compared to copper, per the Plastic Pipe and Fittings Association (PPFA).
Step 5: Install the Drain and Trap
The shower drain must connect to a 2-inch waste line with a P-trap to prevent sewer gases. Slope the pipe at ¼ inch per foot toward the main stack. Test for leaks with a temporary cap and water fill before sealing.
Step 6: Vent the System
Every drain needs a vent within 5 feet (per IPC code) to allow air flow and prevent siphoning. If no existing vent is nearby, you may need an Air Admittance Valve (AAV)—check local approval first.
This is non-negotiable. Apply a liquid membrane (like RedGard) or sheet membrane over backer board. Extend it 3 inches above the shower head and seal all seams. Skipping this risks mold and structural damage.
Step 8: Install Shower Base or Pan
Set a pre-sloped acrylic base or build a custom mud bed. Ensure it’s level and sealed at the drain flange. Let adhesives cure per manufacturer instructions (usually 24 hours).
Step 9: Finish Walls and Fixtures
Tile or install wall panels. Then mount the shower arm, head, and trim kit. Turn water back on slowly and test for leaks at all connections.
While DIY saves money, some scenarios demand a licensed plumber:
No nearby drain or water lines (requires rerouting through floors/walls)
Working in a concrete slab foundation
Local code requires inspection or licensed work
You’re unsure about soldering or pressure testing
The average cost to install a shower ranges from $1,500 to $5,000, according to HomeAdvisor (2025 data). But doing part of the work yourself (like demo or tiling) can cut costs by 30%.
A: Yes—if you can run new supply and drain lines. Half-baths are commonly converted, but expect higher labor due to new plumbing runs.
Q2: Do I need a permit to add a shower?
A: In most U.S. cities, yes. Permits ensure safety and code compliance. Unpermitted work can void insurance or complicate home sales.
Q3: How long does the installation take?
A: A skilled DIYer may finish in 3–5 days. Professionals often complete it in 2–3 days, depending on complexity.
Q4: Can I use PEX instead of copper?
A: Absolutely. PEX is code-approved nationwide, easier to install, and resistant to corrosion. Just ensure fittings are compatible with your water chemistry.
Q5: What’s the minimum space required for a shower?
A: The International Residential Code (IRC) requires at least 30” x 30” of clear space inside the shower. For comfort, 36” x 36” is ideal.
Q6: How do I test for leaks after installation?
A: Cap the shower head outlet, turn on water, and pressurize the system for 15 minutes. Check all joints. Also, fill the drain with water to test the trap seal.
Conclusion
Now you know exactly how to install plumbing for shower in an existing bathroom—from planning to final testing. Whether you’re boosting your home’s value or just craving a spa-like experience, this upgrade is totally achievable with patience and preparation.
✅ Key Takeaways:
Plan around existing plumbing to save time and money
Never skip waterproofing or venting
Use PEX for easier DIY installation
Know when to call a pro
If this guide helped you, share it on Pinterest or Facebook to help other DIYers! Got questions? Drop them in the comments—we love helping homeowners succeed.
Remember: Great bathrooms start with smart plumbing. 🚿
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