Cost of Plumbing Rough-In for 2 Bathrooms (No Fixtures)

Planning a bathroom build or renovation? You’re likely focused on design—but don’t overlook the hidden work that makes everything functional: plumbing rough-in. If you’re asking, “What’s the cost of plumbing rough-in for 2 bathrooms no fixtures?”, you’re not alone. Many homeowners and builders need clarity on this essential (yet often misunderstood) phase before fixtures are even chosen. The good news? We break down real-world 2025 costs, regional differences, and what actually drives your bill—so you can budget with confidence.

What Is a Plumbing Rough-In (And Why Does It Matter)?

A plumbing rough-in is the first installation phase where plumbers run water supply lines, drainpipes, and vent stacks through walls, floors, and ceilings—before drywall goes up. Fixtures like sinks, toilets, and showers aren’t installed yet, but all the “guts” are in place and pressure-tested.

This stage is critical because:

• It sets the foundation for all future plumbing functionality.
• Mistakes are costly to fix once walls are closed.
• Permits and inspections usually happen at this stage.

According to the National Association of Home Builders (NAHB), rough-in plumbing accounts for 30–40% of total plumbing costs in new construction.

Average Cost of Plumbing Rough-In for 2 Bathrooms (No Fixtures)

The national average cost in 2025 for roughing-in plumbing for two standard bathrooms without fixtures ranges from $3,000 to $6,500.

But why such a wide range? Several factors influence the final price:

💡 Pro Tip: If you’re building new, rough-in costs are significantly lower than retrofitting in an existing home. Always confirm whether your quote includes permits and inspections—some contractors exclude them.

Key Cost Drivers Explained

1. Labor Costs Vary by Region

Plumbers in cities like New York or San Francisco often charge 2–3x more than those in the Midwest or South. The U.S. Bureau of Labor Statistics reports average plumbing labor rates between $50 and $130 per hour, with 2-bathroom rough-ins typically taking 20–35 hours.

2. Pipe Material Choices

• PEX tubing: Most common in modern builds—flexible, freeze-resistant, and cost-effective.
• PVC/ABS: Used for drain lines—durable and inexpensive.
• Copper: Durable but expensive; often avoided in new rough-ins due to cost and labor.

Switching from copper to PEX can save $800–$1,500 on a two-bathroom job.

3. Bathroom Complexity

A standard bathroom includes:

• 1 shower/tub
• 1 sink
• 1 toilet

But add features like:

• Double vanities
• Heated towel racks
• Steam showers
  …and you’ll need extra supply lines, drains, and possibly dedicated vents—each adding $150–$400 to rough-in costs.

4. Permits and Inspections

Most municipalities require plumbing permits for rough-ins. Fees average $100–$300, and skipping them can void insurance or delay occupancy.

Step-by-Step: What Happens During a 2-Bathroom Rough-In?

Here’s exactly what a licensed plumber does—no guesswork:

1. Review blueprints and plumbing layout with the contractor or homeowner.
2. Install main water supply line (typically ¾” PEX) to the bathroom zone.
3. Run hot and cold supply lines (½” PEX) to each fixture location:
   • 2 lines per sink
   • 2 lines for shower/tub (hot + cold)
   • 1 cold line for toilet
4. Install drain-waste-vent (DWV) system:
   • 2″ drain for shower/tub
   • 1.5″ drain for sink
   • 3″ drain for toilet
   • Vent pipes tied into main stack (to prevent suction issues)
5. Pressure-test all lines (minimum 60 PSI for 15 minutes—per IPC code).
6. Schedule municipal inspection before drywall.

✅ Note: No fixtures are installed—only stub-outs (exposed pipe ends) are left capped for later connection.

DIY vs. Hiring a Pro: Is It Worth the Risk?

While YouTube tutorials make plumbing look simple, 85% of DIY plumbing failures occur during rough-in (per HomeAdvisor’s 2024 Home Services Report). Common mistakes:

• Incorrect pipe slope → slow drains or backups
• Missing vents → gurgling toilets and sewer smells
• Undersized supply lines → low water pressure

Unless you’re a licensed plumber or have extensive experience, hire a professional. The average cost of fixing DIY errors? $1,200–$3,000—not to mention time and stress.

⚠️ Legal Note: In most U.S. states, plumbing work must be done by a licensed contractor to pass inspection. Check your local regulations at your city’s building department website or via Wikipedia’s overview on plumbing codes in the U.S..

Cost-Saving Tips Without Sacrificing Quality

You don’t have to overpay. Try these strategies:

• Bundle projects: Combine rough-in with HVAC or electrical rough-ins for potential contractor discounts.
• Choose PEX over copper: Saves time and material without compromising performance.
• Plan fixture locations early: Avoid last-minute changes that require rerouting pipes.
• Get 3+ quotes: Prices can vary by 40% between plumbers—even in the same ZIP code.

FAQ Section

Q1: Does “no fixtures” mean I save money?

Yes—but only on materials. Labor for rough-in is largely unchanged whether fixtures are included or not. Fixtures are installed later during the “trim-out” phase, which is billed separately.

Q2: How long does a 2-bathroom rough-in take?

Typically 2–4 days, depending on crew size and home complexity. New construction is faster than retrofits.

Q3: Can I rough-in plumbing before pouring a slab?

Only if using a slab-penetrating system (like a “wet wall”). Otherwise, stub-outs must be placed before concrete is poured—coordinates must be exact.

Q4: Are water heaters included in rough-in?

No. Water heater installation is part of the trim-out or a separate mechanical trade. However, the supply and gas/electric lines to the heater are run during rough-in.

Q5: What’s the cheapest way to rough-in two bathrooms?

Use PEX for supply lines, PVC for drains, stick to standard layouts, and hire during the off-season (late fall/winter) when contractors offer discounts.

Q6: Will my rough-in pass inspection?

If done by a licensed plumber following the International Plumbing Code (IPC), yes. Common fails include improper venting, wrong pipe slopes, or missing cleanouts.

Conclusion

Understanding the cost of plumbing rough-in for 2 bathrooms no fixtures empowers you to make smart, budget-friendly decisions—without compromising safety or functionality. From $3,000 to $6,500, your investment covers the unseen foundation that keeps water flowing and waste moving for decades.

✅ Key takeaways:

• Labor and layout matter more than fixtures at this stage.
• Never skip permits or inspections.
• PEX + professional installation = best value.

Found this guide helpful? Share it on Pinterest, Facebook, or with your contractor group—someone else is probably wondering the same thing! Got questions? Drop them in the comments below.