How to Remove Plumbing Under Sink at Back of Cabinet

Tackling plumbing work under your kitchen or bathroom sink can feel intimidating—especially when pipes are tucked tightly against the back of the cabinet. Whether you’re replacing a faucet, fixing a leak, or installing a new garbage disposal, knowing how to remove plumbing under sink at back of cabinet is a crucial skill for any homeowner. Don’t worry—you don’t need to be a pro plumber to do this right. With the right tools, a clear plan, and a little patience, you can complete this task safely and effectively.

Why Is Plumbing Under the Sink So Hard to Access?

Many homeowners struggle with plumbing behind the sink because cabinets weren’t designed with easy maintenance in mind. According to the National Kitchen & Bath Association (NKBA), over 68% of kitchen remodels involve updating or repairing under-sink plumbing—but poor access remains a top frustration.

Common challenges include:

• Tight clearance between pipes and cabinet back wall
• Cramped working space (often less than 12 inches deep)
• Obstructive supply lines, P-traps, or shutoff valves

Understanding these constraints helps you prepare better—and avoid damaging pipes or cabinetry.

What Tools Do You Need to Remove Under-Sink Plumbing?

Before you start, gather these essential tools:

✅ Adjustable wrench or basin wrench
✅ Bucket or shallow pan (to catch residual water)
✅ Flashlight or headlamp
✅ Plumber’s tape (Teflon tape)
✅ Channel-lock pliers
✅ Screwdrivers (flathead and Phillips)
✅ Towels or rags

Pro Tip: A basin wrench is highly recommended for reaching nuts behind the sink—it’s specifically designed for tight spaces where standard wrenches won’t fit.

Step-by-Step: How to Remove Plumbing Under Sink at Back of Cabinet

Follow these steps carefully to avoid leaks, damage, or injury:

Step 1: Turn Off the Water Supply

Locate the shutoff valves under the sink (usually two: hot and cold). Turn them clockwise until tight. If no valves exist, shut off the main water supply to your home.

⚠️ Never skip this step! Even a small amount of water pressure can cause flooding once pipes are disconnected.

Step 2: Drain Remaining Water

Open the faucet to release pressure and drain residual water from the lines. Place a bucket underneath to catch drips from the P-trap.

Step 3: Disconnect Supply Lines

Use an adjustable wrench to loosen the nuts connecting the supply lines to the faucet tailpieces. Hold the valve steady to prevent twisting the pipe.

Most modern supply lines use compression fittings that require only hand-tightening plus a quarter-turn with a wrench—overtightening can crack fittings.

Step 4: Remove the P-Trap

Place your bucket directly under the P-trap. Loosen the slip nuts on both ends using channel-lock pliers. Gently lower the trap to drain any standing water.

The P-trap is required by plumbing codes to prevent sewer gases from entering your home (see U.S. plumbing standards).

Step 5: Detach Faucet or Fixture Mounting Hardware

If removing the entire faucet, locate the mounting nuts under the sink that secure it to the countertop. Use a basin wrench to loosen them—they’re often hidden against the cabinet back.

For tight spots, try a flex-head basin wrench—it pivots to reach awkward angles.

Step 6: Carefully Pull Out Plumbing Components

Once all connections are free, gently pull the plumbing assembly away from the back of the cabinet. Avoid yanking; some pipes may be adhered with old putty or sealant.

Step 7: Clean the Area

Wipe down the cabinet interior and inspect for mold, leaks, or rot. This is also a great time to add a moisture barrier or organize future access with pipe clips.

Common Mistakes to Avoid

When Should You Call a Professional Plumber?

While most under-sink plumbing removal is DIY-friendly, call a licensed plumber if:

• Pipes are corroded, frozen, or fused together
• You smell sewer gas after disassembly
• Your home has galvanized steel pipes (common in pre-1980 builds)
• Local codes require permits for plumbing work

The U.S. Bureau of Labor Statistics reports that professional plumbers resolve 92% of residential plumbing issues on the first visit—so don’t risk major damage if you’re unsure.

FAQ Section

Q1: Can I remove under-sink plumbing without turning off the water?

No. Even a small amount of pressure can cause significant water damage. Always shut off the supply valves or main water line first.

Q2: Why is there so little space behind my sink pipes?

Cabinet manufacturers prioritize storage over service access. Older homes often have even tighter clearances due to non-standard installations.

Q3: Do I need to replace the P-trap when removing plumbing?

Not necessarily. If it’s PVC and in good condition, you can reuse it. Replace if cracked, warped, or leaking.

Q4: What if the mounting nut is stuck against the cabinet back?

Use a basin wrench with a long handle and swivel head. Spray penetrating oil (like WD-40) and let it sit for 10 minutes before trying again.

Q5: How long does it take to remove under-sink plumbing?

For beginners: 30–60 minutes. Experienced DIYers can do it in 15–20 minutes once familiar with the setup.

Q6: Can I reuse old supply lines?

Only if they’re braided stainless steel and show no kinks, cracks, or corrosion. Most experts recommend replacing them every 5–7 years.

Conclusion

Now you know exactly how to remove plumbing under sink at back of cabinet—safely, efficiently, and without stress. Whether you’re upgrading fixtures, fixing leaks, or prepping for a renovation, mastering this skill saves you time and hundreds in labor costs.

✅ Key benefits you’ve gained:

• Confidence to handle common plumbing tasks
• Knowledge to avoid costly mistakes
• Ability to inspect and maintain hidden areas

Found this guide helpful? Share it on Facebook, Pinterest, or Twitter to help fellow DIYers tackle their next project with ease! And don’t forget to leave a comment below—we love hearing about your successes (and lessons learned!).

Remember: Good plumbing isn’t just about pipes—it’s about peace of mind. 💧🔧