How to Replace Your Sink Drain Like a Pro

Ever looked under your bathroom sink and noticed an accordion-style drain? These flexible pipes may seem convenient, but they often trap debris, breed bacteria, and can leak or smell over time. In this guide, we’ll show you how to replace that accordion drain with a proper P-trap setup, step by step. You’ll get a cleaner, more reliable drain—no specialized plumbing license required.

Why Ditch the Accordion Drain?

• Bacteria and Mold: Corrugated pleats trap hair, soap scum, and other debris, encouraging mildew and mold growth.
• Leaks and Smells: All those folds and cheap plastic connections often lead to poor seals.
• Code Compliance: Many areas discourage accordion drains because they don’t meet certain plumbing standards.

Tools and Materials You’ll Need

1. Bucket or Dishpan: To catch water when you remove the old drain.
2. Towels or Rags: Essential for cleanup.
3. Adjustable Pliers or Channel Locks: Handy for loosening or tightening nuts.
4. New P-trap Assembly: Make sure you match the diameter (usually 1 1/4 or 1 1/2 inches).
5. Pipe Extension (optional): May be needed if your existing stub-out is short or offset.
6. Permanent Marker: Useful for marking cut lengths and insertion depth.
7. Tape Measure: To get accurate cut lengths on your extension pipe if needed.
8. PVC Cutter or Hacksaw: For trimming your new extension or P-trap tailpiece to fit.

Step 1: Disassemble the Old Drain

1. Set up your bucket under the sink to catch any standing water in the trap.
2. Loosen the connections on the accordion drain and the existing trap (if any). Use adjustable pliers if they’re overtightened.
3. Remove the old trap and drain pieces carefully, letting water drain into your container.
4. Clean and wipe the inside of the tailpiece (where it meets the sink) and the stub-out at the wall to remove any old debris or buildup.

Tip: Resist the urge to dump trap water back into your sink—always discard into a bucket or dishpan to avoid making a mess in your bowl or fixture.

Step 2: Check Your P-Trap Size

• Measure the outside diameter of the pipe stub-out from the wall or your existing drain tailpiece.
• Common sizes are:
  • 1 1/4 inch (often for bathroom sinks)
  • 1 1/2 inch (kitchen sinks or certain bath configurations)

Buy a P-trap kit that matches your sink’s tailpiece diameter. If needed, also pick up an adapter washer if you must transition from 1 1/4 to 1 1/2.

Step 3: Dry-Fit the New P-Trap

1. Assemble the trap loosely to see how it lines up with the sink tailpiece and wall stub-out.
2. Mark and cut any extension pipe or the tailpiece so that the trap aligns properly.
3. Slide on all necessary nuts and washers (the beveled side of the washer typically faces the direction of water flow).

Pro Tip: If you’re using a plastic tailpiece, use a PVC cutter or hacksaw for a clean, straight cut. Then remove burrs and smooth edges.

Step 4: Final Assembly

1. Attach the trap bend to the tailpiece with its dedicated nut and washer. Hand-tighten first.
2. Connect the trap arm from the trap bend to the stub-out on the wall.
3. Ensure the correct washers (and reducer washers if needed) are in place.
4. Hand-tighten all joints, checking alignment.
5. Lightly snug with adjustable pliers, but avoid overtightening—you can crack plastic nuts.

Step 5: Testing for Leaks

1. Close or block the sink drain, then fill the sink with water.
2. Carefully open the drain (unblock or flip up the pop-up).
3. Observe the new trap connections from underneath, checking for any drips.
4. Run water for 1–2 minutes. If no leaks appear, you’re set.
5. Pat dry and place a paper towel under the trap for the next day or so. If the towel remains dry, you have a solid install.

Frequently Asked Questions

Q: Do I really need to replace an accordion drain if it’s not leaking?
A: Yes. While it may not be dripping now, the pleats trap debris and can emit odors. A smooth-walled P-trap is always better long-term.

Q: Can I reuse any parts from the old assembly?
A: Possibly the tailpiece if it’s in good condition, but usually the accordion section is the issue. Often it’s best to replace everything with new washers, nuts, and trap components.

Q: What if the stub-out from the wall doesn’t line up with the sink tailpiece?
A: A 45-degree or 22.5-degree bend might be necessary. Or you may extend the tailpiece slightly. Adaptors and short lengths of pipe make almost any offset workable.

Wrap-Up

Removing that old accordion drain and installing a proper P-trap is more than just a cosmetic upgrade. It prevents clogs, reduces odors, and brings your bathroom back to professional standards. With a few tools and a little patience, you’ll have a smooth, leak-free drain that’s easier to maintain and lasts for years.