How to Plumb a Shower Drain in Concrete: A Step-by-Step Guide for DIYers

Why This Matters: Getting It Right the First Time

If you’re planning to install a shower in a concrete slab—whether it’s a basement renovation, a new build, or a bathroom remodel—you’ve probably realized one thing: plumbing a shower drain in concrete isn’t like snapping together PVC pipes in a framed wall. One mistake, and you could be facing mold, structural damage, or even a complete tear-out.

You’re not alone. According to the National Association of Home Builders (NAHB), over 60% of bathroom remodels in older homes require plumbing corrections—and nearly half of those involve improper drain installation in concrete slabs. The good news? With the right tools, knowledge, and patience, you can do this right. And we’re here to walk you through every step.

This guide isn’t just theory. It’s based on real-world installations, plumbing codes (IPC & UPC), and advice from licensed contractors who’ve fixed hundreds of failed drains. Let’s get your shower draining like it should—fast, quiet, and leak-free.

What Tools and Materials Do You Need to Plumb a Shower Drain in Concrete?

Before you break ground—or concrete—you need the right gear. Here’s your checklist:

💡 Pro Tip: Always use PVC or ABS, not cast iron or copper, for shower drains in concrete. They’re easier to cut, seal, and adjust in-slab.

Can You Install a Shower Drain After Concrete Is Poured?

Yes—but it’s harder.

If your concrete slab is already cured (typically 28 days), you’ll need to cut into it. This is called a “slab cut” and requires precision. According to The Spruce, over 70% of DIYers who attempt this without proper tools end up cracking the slab or hitting rebar.

Best practice:
Plan your drain location before pouring concrete. But if you’re working with an existing slab:

• Use a diamond blade saw to cut a 12″x12″ square around your intended drain location.
• Cut no deeper than 4–5 inches unless you’re certain of what’s below (avoid electrical, gas, or sewer lines).
• Always call 811 (USA’s “Call Before You Dig” service) to mark underground utilities. It’s free—and legally required.

📌 “A poorly cut slab isn’t just messy—it’s dangerous. One wrong cut can compromise structural integrity.”
— Mike Holmes, licensed plumber and TV home improvement expert

Step-by-Step: How to Plumb a Shower Drain in Concrete (7 Easy Steps)

Let’s break this down into manageable, foolproof steps.

Step 1: Mark the Drain Location

• Place the drain flange where you want the shower to sit (center of the room is ideal).
• Use chalk or painter’s tape to trace the outline.
• Ensure it’s at least 3 feet from any other fixture to meet code (IPC Section 405.2).

Step 2: Cut the Concrete

• Use a concrete saw to cut a 12″ x 12″ square.
• Cut 4–5 inches deep—deep enough to reach below the slab’s rebar mesh (usually 2–3″ below top surface).
• Remove debris with a shop vacuum.

Step 3: Install the Drain Pipe

• Slide the vertical drain pipe (PVC/ABS) down into the hole.
• Connect it to the main sewer line using a flexible coupling.
• Slope the pipe at ¼ inch per foot toward the main sewer. Use a laser level to check.
• Example: If your drain is 6 feet from the main stack, the pipe must drop 1.5 inches over that distance.

Step 4: Secure the Drain Flange

• Attach the drain flange to the top of the vertical pipe using PVC primer and cement.
• Make sure the flange sits flush with the future shower pan surface.
• Use construction adhesive (like Liquid Nails) around the flange’s outer edge to seal it to the concrete.

Step 5: Build the Shower Pan Base

• Pour a 1–2 inch layer of clean sand over the cut area.
• Add gravel (½” size) for drainage support.
• Use a tamper or flat board to compact and level the base.
• Place a waterproof membrane (RedGard or Schluter-DITRA) over the entire area, extending 6″ up the walls.

Step 6: Pour the Shower Pan Mortar

• Mix mortar (3 parts sand, 1 part Portland cement) with water to a thick, peanut butter-like consistency.
• Slope the mortar toward the drain at ¼ inch per foot.
• Use a straightedge to screed the surface—this is critical for proper drainage.
• Let cure for 24–48 hours before proceeding.

Step 7: Install the Final Drain Cover & Tile

• Once mortar is cured, install the final drain grate.
• Apply waterproofing again over the entire shower floor (yes, twice!).
• Tile over the surface with thinset mortar and grout.
• Test the drain with 2 liters of water (about ½ gallon). Watch for pooling or slow drainage.

✅ Code Check: According to the International Plumbing Code (IPC), shower drains must handle 5 gallons per minute without backup. A properly sloped 2″ drain easily meets this.

Shower Drain Types: Which One Works Best in Concrete?

Not all drains are created equal. Here’s what professionals use:

🔍 Expert Insight: “For 95% of residential concrete slabs, a standard 2” PVC flange drain is the smartest choice. It’s reliable, repairable, and meets every U.S. code.” — Plumbing Today Magazine, 2024

Common Mistakes to Avoid When Plumbing a Shower Drain in Concrete

Don’t let these 5 errors cost you thousands:

1. No slope → Water pools → Mold grows → Floor rots.
2. Using silicone instead of PVC cement → Leaks within weeks.
3. Cutting too deep → Hits rebar or utility lines.
4. Skipping the waterproof membrane → Water seeps into slab → Structural damage.
5. Installing drain after tiling → Impossible to fix without demolition.

🚫 Myth Busting: “You can just glue the drain to the concrete.”
Truth: Concrete isn’t a sealant. Only PVC cement + flange + membrane creates a watertight barrier.

FAQ: Your Top Questions About Shower Drains in Concrete

Q1: Can I use a shower drain without a P-trap in concrete?

No. Every shower drain must have a P-trap (U-shaped pipe) to prevent sewer gases from entering your home. The trap must be installed below the slab, not above it. According to the International Residential Code (IRC), the trap seal must be at least 2 inches deep. Learn more about traps on Wikipedia .

Q2: How deep should the concrete slab be for a shower drain?

Most residential slabs are 4 inches thick. For shower drains, you need at least 6–7 inches of total depth from the finished floor down to the sewer line. This includes:

• 1–2″ for mortar bed
• 1–2″ for pipe and fittings
• 2–3″ for slab thickness

Q3: How long does it take to plumb a shower drain in concrete?

For a skilled DIYer: 8–12 hours total.
Breakdown:

• Cutting concrete: 2–3 hrs
• Installing pipe: 1 hr
• Mortar curing: 24–48 hrs
• Tiling: 4–6 hrs

Plan for 2 full days minimum.

Q4: Do I need a permit to plumb a shower drain in concrete?

Yes. In nearly all U.S. municipalities, any plumbing modification requires a permit—especially when cutting into a slab. Skipping it can void your home insurance and cause issues during resale. Always check with your local building department.

Q5: Can I install a shower drain over an existing tile floor?

Technically, yes—but it’s not recommended. You’d need to remove tiles, cut concrete, and re-tile. It’s almost always cheaper and more reliable to do it right the first time during a full remodel.

Q6: What’s the average cost to plumb a shower drain in concrete?

• DIY: $150–$300 (materials only)
• Professional: $800–$1,500 (includes labor, permit, demo)
  Labor accounts for 70% of the cost. If you’re handy, DIY saves you hundreds.

Final Thoughts: Your Shower Deserves a Solid Foundation

Plumbing a shower drain in concrete isn’t a weekend project—it’s a lifetime investment. Get it right, and your bathroom will stay dry, odor-free, and code-compliant for decades. Get it wrong, and you’ll be dealing with rot, mold, and a very expensive fix.

You now have the exact steps, tools, and expert tips used by pros. No guesswork. No shortcuts. Just results.

👉 Ready to take action?
Grab your tools, mark your drain spot, and start cutting. When you’re done, snap a photo of your finished drain and share it on Instagram or Facebook with #ConcreteShowerDrainPro. We’d love to see your success!

And if you found this guide helpful, share it with a friend who’s tackling a bathroom remodel. One well-plumbed drain can save someone thousands.