A slow draining shower tray is one of the most common household plumbing annoyances in New Zealand, and the good news is you can usually fix it yourself without reaching for a bottle of caustic drain cleaner. In most cases, the culprit is a build-up of hair, soap scum, and body oils sitting just below the drain cover — and it can be removed with a few basic tools and a bit of patience.
Why Avoid Chemical Drain Cleaners?
While chemical drain cleaners are widely available, they come with real downsides. Caustic or acid-based products can damage older PVC pipework, corrode chrome fittings, and are hazardous to handle. They're also hard on the environment once they enter the wastewater system. Mechanical methods are safer, just as effective for most blockages, and won't risk damaging your plumbing.
What You'll Need
Before you start, gather these items — most are available at Bunnings or Mitre 10:
- Rubber gloves
- Old toothbrush or small scrubbing brush
- Flathead screwdriver or drain cover removal tool
- Drain snake (also called a plumber's auger) or a zip-it drain cleaning tool
- Bucket and old rags
- White vinegar and baking soda (optional natural alternative)
- Torch or phone light
Step 1 — Remove the Drain Cover
Most shower drain covers either unscrew with a flathead screwdriver or simply lift out. Some snap into place and need a gentle lever with a screwdriver. Once removed, clean the cover itself — soap scum and hair often clog the slots. An old toothbrush works well here.
Safety note: Always wear rubber gloves. Drain gunk can harbour bacteria.
Step 2 — Clear Visible Debris by Hand
Shine a torch into the drain opening. In many cases you'll see a clump of hair sitting just a few centimetres down. Use your fingers (gloved) or a pair of needle-nose pliers to pull it out. It's unpleasant but effective. Remove as much as you can see.
Step 3 — Use a Zip-It Tool or Drain Snake
A zip-it tool is a long, flexible plastic strip with barbs along the sides — it's inexpensive and excellent for pulling hair out of shower drains. Insert it into the drain, twist it gently, and pull back slowly. You may need to repeat this several times.
For deeper blockages, a hand-operated drain snake (auger) can reach further into the pipe. Feed the cable into the drain, turn the handle clockwise to work it through the blockage, then pull back to retrieve the debris.
Step 4 — Flush with Boiling Water or a Baking Soda Mix
Once you've removed the physical blockage, flush the drain to clear any remaining residue:
- Boiling water method: Carefully pour a full kettle of boiling water down the drain in two or three stages, allowing it to work between pours. Note: Only use boiling water if your pipes are PVC in good condition or copper — avoid this with older, fragile pipes or acrylic shower trays where the drain fitting may be plastic.
- Baking soda and vinegar method: Pour half a cup of baking soda into the drain, followed by half a cup of white vinegar. Cover the drain opening and leave for 15–20 minutes. The fizzing action helps loosen soap scum. Flush with hot (not boiling) water afterwards.
Neither of these is a chemical drain cleaner — they're gentle, safe for most plumbing, and environmentally friendly.
Step 5 — Replace the Drain Cover and Test
Refit the drain cover and run the shower for a minute or two to check the flow. If the water drains freely, you're done. If it's still slow, the blockage may be further down the pipe.
Preventing Future Blockages
A little maintenance goes a long way:
- Install a drain hair catcher — a simple mesh insert that sits over or in the drain and catches hair before it enters the pipe. Clean it after every shower.
- Flush the drain with hot water weekly.
- Do a baking soda and vinegar flush monthly as routine maintenance.
- Avoid washing large amounts of hair product or thick conditioner down the drain at once.
Understanding Your Shower Drain System
In New Zealand, shower drainage must comply with the NZ Building Code, particularly Clause G13 (Foul Water). Your shower trap — the curved section of pipe beneath the drain — is designed to hold a small amount of water that blocks sewer gases from entering your home. If your shower drain gurgles, smells of sewage, or drains slowly even after clearing the visible blockage, the trap itself may be partially blocked or, in older homes, may have dried out or failed.
For more on how drainage systems should perform, BRANZ and MBIE Building Performance are useful NZ-specific references.
When to Call a Professional
Some drain issues are beyond a DIY fix. Call a licensed plumber if:
- The drain is still slow after clearing visible blockages and snaking the pipe
- Multiple drains in your home are slow at the same time (this suggests a main drain blockage)
- You notice gurgling from other fixtures when the shower runs
- There's a persistent sewage smell even after cleaning
- You suspect a broken or collapsed pipe
Plumbing work that involves modifying or repairing drain pipework beyond basic unblocking is restricted work under the Plumbers, Gasfitters and Drainlayers Act 2006. It must be carried out by a licensed tradesperson registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB). Attempting restricted work yourself is illegal and could void your home insurance.
You can find a qualified local plumber on tradedirectory.co.nz to get the job sorted quickly and correctly.
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