How to Clean a Shower Drain (and Keep It Smell-Free)
Quick answer: The best way to clean a shower drain is to clear visible hair, flush with hot water, then add a non-caustic drain treatment and leave it overnight to break down the hair, soap scum and biofilm causing odours and slow draining. Avoid caustic cleaners — they damage pipes and don't remove the underlying biofilm, so the problem returns.
A slow, smelly shower drain is one of those jobs everyone puts off. But the longer you leave it, the worse the build-up of hair, soap scum and biofilm gets. Here's how to clean a shower drain properly — and keep it flowing freely.
Why shower drains get blocked and smelly
Shower drains rarely block from one thing. They clog from a slow build-up of hair (the main culprit), soap scum, body oils, conditioner residue, and a layer of biofilm — slimy bacteria coating the inside of the pipe. The biofilm is what causes the smell, and it's exactly what bleach can't reach.
What you'll need
- A non-caustic drain cleaner (we use DRAINZAP)
- Disposable gloves (optional)
- A drain tool or wire hook for visible hair
How to clean a shower drain: step-by-step
- Remove the drain cover and clear visible hair. Pull off the cover and remove any hair mat with a gloved hand or drain tool.
- Flush with hot water for 30 seconds. This warms the pipe and softens soap scum, improving the treatment's effectiveness.
- Pour in the recommended dose of DRAINZAP. Add it directly to the drain — don't dilute. Concentrated formula works best.
- Leave overnight. Don't use the shower. The treatment needs time to break down the hair, soap scum and biofilm.
- Flush with hot water in the morning. Run hot water for 1-2 minutes to clear the dissolved blockage and rinse the pipe.
Why not just use bleach or caustic cleaner?
Bleach masks the smell briefly but can't penetrate biofilm. Caustic (sodium hydroxide) cleaners burn through blockages but damage pipes over time, produce dangerous fumes, harm septic systems, and leave the biofilm behind. A non-caustic treatment breaks down the actual cause instead.
How to keep your shower drain clear
- Use a hair catcher over the drain
- Monthly non-caustic dose to keep biofilm in check
- Weekly hot-water flush to stop soap scum setting
The non-caustic way to a fresh, free-flowing drain
At Thrive we match the science to the problem: probiotic biotechnology in MULTIZAP for organic residue and odour, and advanced clean chemistry in MOULDZAP and DRAINZAP for mould, scale and drain build-up.
Frequently asked questions
Why does my shower drain smell?
Shower drain odour comes from biofilm — a slimy layer of bacteria growing inside the pipe that feeds on hair, soap scum and body oils. Bleach only treats the surface; you need a treatment that breaks down the biofilm at the source.
What's the best thing to clean a shower drain with?
A non-caustic drain treatment is the safer, more thorough option. It breaks down the hair, soap scum and biofilm behind slow drains and odours, without damaging pipes or harming septic systems the way caustic chemicals do.
How often should I clean my shower drain?
A monthly maintenance dose keeps biofilm and soap scum from building up. If you have long hair in the household, a fortnightly hair-catcher clean-out plus monthly treatment works best.
Can I use caustic drain cleaner in my shower?
You can, but it's not recommended. Caustic (sodium hydroxide) cleaners can damage pipes and seals with repeat use, produce dangerous fumes, harm septic systems, and don't remove the underlying biofilm — so the problem returns.
Is a non-caustic drain cleaner safe for septic tanks?
Yes. Non-caustic drain treatments are septic-safe because they don't kill the bacteria a septic system relies on, unlike bleach and caustic cleaners which disrupt the septic system's balance.