A blocked bathroom sink is one of the most common household plumbing headaches, and a drain snake (also called a plumber's auger or drain auger) is often the most effective DIY solution. Unlike chemical drain cleaners, a drain snake physically breaks up or retrieves the blockage — usually a build-up of hair, soap scum, and toothpaste — without damaging your pipes.
What Is a Drain Snake?
A drain snake is a long, flexible coiled cable with a corkscrew or hook tip. You feed it down the drain, rotate it to grab or break up the blockage, then pull it back out. They come in two main types:
- Hand-cranked (manual) auger – typically 3–10 metres long, ideal for bathroom sinks. Available from Bunnings or Mitre 10 for a broad guide price of around $30–$80.
- Electric or drill-powered auger – better for stubborn or deeper blockages, but requires more care to avoid pipe damage.
For most bathroom sink blockages, a manual hand-cranked snake is all you need.
Tools and Materials You'll Need
- Drain snake (manual auger)
- Bucket
- Old towels or rags
- Rubber gloves
- Needle-nose pliers (optional)
- Torch/flashlight
- Pipe wrench (if removing the P-trap)
Step-by-Step: How to Snake a Bathroom Sink Drain
1. Remove the Pop-Up Stopper
Most bathroom sinks have a pop-up stopper — the small plug controlled by a rod behind the tap. Lift it out by hand or unscrew it. If it won't budge, reach under the sink and disconnect the pivot rod from the clevis strap (the horizontal bar). Clean any hair and gunk off the stopper while you're at it — this alone sometimes fixes a slow drain.
2. Check the P-Trap First
Place your bucket under the curved pipe beneath the sink (the P-trap). Unscrew the slip-joint nuts by hand or with a pipe wrench and remove the P-trap. Blockages often sit right here. Clear it out, rinse it, and refit it. If the blockage is further in, move to the next step.
3. Feed the Snake Into the Drain
With the P-trap removed, you can feed the snake directly into the drain pipe in the wall — this gives you a clearer path. If you've refitted the P-trap, feed the snake through the drain opening in the sink basin.
Loosen the thumbscrew on the snake's handle to allow the cable to extend, then gently push the cable into the drain opening.
4. Rotate and Advance
Once you feel resistance, tighten the thumbscrew to lock the cable, then turn the handle clockwise while applying gentle forward pressure. The rotating tip will either break up the blockage or hook into it. Avoid forcing the snake — if it won't advance, pull back slightly and try again.
5. Pull Out the Blockage
When you feel the resistance ease or the snake hook into something, slowly pull the cable back out while continuing to rotate clockwise. Have your bucket and rags ready — it will likely bring up a clump of hair and debris. Dispose of it in the bin, not back down the drain.
6. Flush and Test
Refit the P-trap if you removed it, making sure the slip-joint washers are seated correctly to prevent leaks. Run hot water for a minute or two to flush the drain and confirm the blockage is clear. Reattach the pop-up stopper.
7. Repeat if Needed
If the drain is still slow, run the snake through a second time. Persistent blockages may sit further along the pipe.
Tips for Success
- Wear rubber gloves — the debris you pull out is unpleasant and can carry bacteria.
- Don't use chemical drain cleaners before snaking — if the chemical is still sitting in the pipe, it can splash back and cause burns.
- Rotate the snake clockwise only when pulling back, to keep debris on the hook rather than releasing it.
- If your sink has an overflow hole (a small hole near the top of the basin), block it with a wet cloth while snaking to maintain pressure.
Preventing Future Blockages
Bathroom sink blockages are almost always caused by hair and soap build-up. A simple drain strainer or hair catcher (available at Bunnings or Mitre 10) placed over the drain opening will catch most debris before it enters the pipe. Clean it weekly. Running hot water down the drain for 30 seconds after each use also helps flush soap residue.
When to Call a Professional
While snaking a bathroom sink drain is straightforward DIY work, there are situations where you should call a licensed plumber:
- The blockage won't clear after two or three attempts with the snake.
- Multiple drains in your home are blocked at the same time — this suggests a problem with the main drain or sewer line.
- You notice gurgling sounds from other fixtures when the sink drains, or sewage smells coming from drains.
- The P-trap or drain pipes are cracked, corroded, or leaking after reassembly.
- You're in a rental property — under the Healthy Homes Standards, landlords are responsible for maintaining drainage in good working order.
Under the NZ Plumbers, Gasfitters and Drainlayers Act 2006, certain plumbing and drainlaying work is restricted and must be carried out by a licensed tradesperson registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB). Clearing a sink blockage yourself is generally fine, but any work that involves cutting into or permanently modifying drain pipes must be done by a licensed plumber.
You can find a qualified local plumber on tradedirectory.co.nz.
Sources & Further Reading
- Plumbers, Gasfitters and Drainlayers Board (PGDB) — licensing and restricted work
- MBIE Building Performance — NZ Building Code and plumbing requirements
- Tenancy Services – Healthy Homes — landlord obligations for drainage
- WorkSafe NZ — safe use of tools and chemicals
- Bunnings — drain snakes, hair catchers and plumbing tools
- Mitre 10 — drain snakes and plumbing supplies
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