How to Unclog a Shower Drain Without Chemicals

Photo by Point3D Commercial Imaging Ltd. on Unsplash (https://unsplash.com/photos/1656646523907-97b094c7e63a)

By Tomo — licensed plumber, Brisbane QLD.

Quick legal note up front: clearing your own shower drain is homeowner-legal in every Australian state. You can use a plunger, a Zip-It tool, or a hand-cranked drain auger without breaking any plumbing law. What’s NOT homeowner-legal is opening up sealed waste pipes, modifying the trap, or doing any work past the floor waste — that’s licensed plumber territory under the Plumbing Code of Australia. This article stays inside the legal homeowner DIY zone.

Last month I got called out to a place in Wilston where the homeowner had emptied three full bottles of caustic drain cleaner over a fortnight trying to clear a slow shower. The drain was as slow as ever and now the rubber seals on his floor waste were swelling and weeping. I pulled out a $3 plastic Zip-It from my van, slid it down the drain, and dragged out a 30 cm hairball that looked like a deceased rat. The whole job took 90 seconds.

The economics of this are wild. A Zip-It costs $3. A bottle of Drano costs about $8. A plumber call-out (mine, anyway, in inner Brisbane) is $180 minimum just to walk in the door. People will spend $24 on three bottles of caustic that doesn’t work, then another $180 on me to do the $3 fix. The Zip-It lives in the cleaning cupboard at my place and gets used every couple of months on someone’s shower as a favour. They’re worth keeping.

Drain snakes (the long flexible cables) are useless on hair clogs because hair just slides off the auger tip. The Zip-It — a flat plastic strip with backward-facing barbs — is what you actually want for the most common Aussie shower clog: hair plus shampoo gunk wrapped around the trap arm. And caustic chemical drain cleaners are genuinely the worst option in an Aussie home because of how our wastes are built.

What you’ll need

Zip-It drain cleaning tool — Bunnings $3, or any disposable plastic drain stick
Phillips #2 screwdriver to remove the grate (most Aussie shower wastes use one or two screws)
Rubber gloves — disposable nitrile is fine, you’re going to want them
Old toothbrush
Plunger (small cup-style, not a flange/toilet plunger)
White King bleach OR enzyme drain cleaner like Actizyme — but NOT caustic drain cleaner
Bucket of hot (not boiling) water
Torch to look down the drain
Bin liner for the hair extraction

Step 1: Diagnose: slow drain, totally blocked, or smell?

Before you start, work out what the actual problem is:

Drains slowly — almost always hair in the trap arm. Zip-It will fix it.
Won’t drain at all — could be a deeper blockage past the trap, may need a plumber.
Drains fine but smells — biofilm coating the inside of the trap, needs cleaning not unclogging.

Step 2: Remove the grate

Most Aussie shower wastes have a square or round chrome grate held down by one or two Phillips screws. Some clip-in grates just lift out with a flathead pry. Once the grate is off, you’ll see the top of the trap. If yours is a 50 mm round drain with no visible trap (just a smooth tube going down), it’s a P-trap directly under — which is the standard Aussie configuration.

Aussie shower waste anatomy: 50 mm grate, short drop to a P-trap directly under the grate. The Zip-It reaches into the trap arm to extract hair.

Step 3: Visual inspection with the torch

Shine the torch down the drain. Nine times out of ten you’ll see the hairball within 50–100 mm of the surface, sitting on top of or just inside the trap. If you can see standing water that’s not draining, the blockage is past your line of sight and you’ll need the Zip-It (or, if that fails, a plumber).

Step 4: Insert the Zip-It

Push the Zip-It straight down into the drain as far as it will go — usually 25–30 cm in an Aussie 50 mm waste. Don’t force it past resistance because that’s where the trap turns and you can crack the trap arm if you push too hard. Once it’s in, the barbs on the Zip-It have engaged whatever’s down there.

Step 5: Pull slowly and steadily

Pull the Zip-It out at a slow, steady pace. The barbs grab the hair and bring it up. You will be horrified by what comes out. This is normal. Have the bin liner open ready for the disposal. Wipe the Zip-It off into the bin liner — don’t rinse it down the same drain you just unclogged.

Step 6: Repeat until you get a clean pull

Run the Zip-It back down two or three more times. Each pull may bring up more debris until you eventually get a clean pull with nothing on it. That’s when you’re done with the mechanical extraction.

Step 7: Why you don’t use caustic drain cleaner

Here’s the Aussie gotcha. Standard caustic drain cleaners (sodium hydroxide based — Drano, Mr Muscle Foamer, etc.) are formulated for US plumbing, which uses 50 mm or 75 mm wastes with no rubber seals at the trap. Aussie shower wastes have rubber compression seals at the trap arm (the ring that clamps the trap to the floor waste), and caustic cleaners attack rubber. Repeated use breaks down the seals, water starts weeping under the floor, and you’ve got a tile-up-and-rebuild repair job that costs $3,000+. Bin the caustic stuff. For maintenance, use enzyme cleaners (Actizyme, Drano Enzyme) that eat organic matter without attacking rubber.

Step 8: Hot water flush — but not boiling

Pour 2–3 litres of hot tap water down the drain to flush any loose debris through. Don’t use boiling kettle water — boiling water can crack the PVC trap (PVC’s softening point is around 80°C) and warp the rubber seals. Hot tap water (around 50–60°C) is plenty.

Step 9: Optional — bleach soak for biofilm and smell

If your drain still smells, the problem is biofilm coating the inside of the trap. Pour 100 ml of White King down the drain, let it sit for 30 minutes, then flush with hot water. Don’t mix bleach with anything else — and don’t use it back-to-back with enzyme cleaners because the bleach kills the enzymes.

Step 10: Replace the grate and prevent recurrence

One extra preventive measure for long-haired households: keep a small handheld silicone bristle brush in the shower and run it across the hair-catcher disc each time you finish showering. Takes 5 seconds, lifts the day’s hair off the disc into the bin, and the disc stays effective. The disc plus weekly empty plus a yearly Zip-It is a maintenance routine that means I never have to see your shower drain again.

Re-screw the grate back on. To stop this happening again, fit a hair-catcher disc — Bunnings sells silicone ones for $4 that sit over the grate and catch hair before it goes down. Empty it weekly. The reason your drain blocked in the first place is that nothing was stopping the hair entering the trap. Five seconds of weekly maintenance saves the 90-second extraction every six months.

Common things that go wrong

If the basic Zip-It approach hasn’t worked, here’s what’s usually happening:

Zip-It comes out clean but the drain’s still slow. The blockage is past the trap (in the waste pipe between the trap and the main stack). That’s beyond DIY — you’d need a 50 mm electric eel, and it’s licensed-plumber territory because you’d have to disturb sealed waste pipework.
Multiple drains in the house slow at the same time. The blockage is in the main sewer line, not your shower. Tree roots in the sewer connection are the most common cause. This is a job for a plumber with a sewer camera and a hydro-jetter.
Drain gurgles when other fixtures run. Vent pipe blocked — bird nest or dirt in the roof vent. That’s plumber territory because the vent is part of the building plumbing.
Persistent sewage smell despite cleaning. Trap has run dry (rare for a shower in regular use) or there’s a cracked trap. Pour 2 L of water down the drain — if the smell goes for a few days then returns, it’s evaporation, fix is a small splash of vegetable oil after each use to slow evaporation. If the smell persists immediately, crack in the trap, plumber call.
Pop-up plug in the drain (some Aussie shower bases have these). The mechanism collects hair like a pop-up basin plug. Lift the plug out (some unscrew, some pop with a twist), clean it separately, replace.

The Tomo rule

Hair clogs need mechanical extraction (Zip-It), not chemical dissolution. Caustic drain cleaners are the wrong tool for Aussie wastes because they attack the rubber compression seals, and you’ll trade a $3 fix for a $3,000 rebuild. Enzyme cleaners and a hair-catcher disc are the actual maintenance routine. And if you can’t reach the blockage with a Zip-It, that’s where homeowner DIY ends — call a licensed plumber rather than escalating to chemicals.

Got a recurring drain blockage that won’t clear with the Zip-It? Send us a write-up.