Nothing ruins a bathroom faster than a shower drain smell that hits you the second you walk in. One person said it best: “We solved the fly problem, but the smell stayed for years and we’ve had enough.”
A bad-smelling shower is one of the top complaints Gold Coast Plumbing and Hot Water gets from homeowners needing drain work.
You clean, you scrub, you pour things down the drain… and yet the smell creeps back.
Smelly shower drains almost always have a clear cause. And once you know what to look for, fixing it becomes much easier.
Below are real tips and insights from plumbers who can see down the drain.
Where the Stink Starts (And How to Spot It)
A cracked or leaking drain pipe under the shower → wastewater can seep out before it reaches the trap and the smell escapes back up into the shower.
Biofilm stuck higher up in the drain (not just in the pipes) → Underside of the drain cover or upper pipe walls where slime clings.
Deteriorated rubber → gaskets rubber fittings around the drain trap moisture. This biofilm can smell awful even if the pipes are clean.
Hot showers releasing trapped odours → Issues with your hot water system can make those smells stronger.
Connected drains in the home → A dry, unused floor drain elsewhere (basement, laundry, spare bathroom) can push odours up through your shower.
Tried-and-Tested Methods to Remove the Stink
A smelly drain doesn’t have to stick around. These methods have helped Aussies finally clear the odour, and they’re easy to follow.
1. Check if the P-Trap Was Installed Properly
Most people don’t realise this, but if your shower smells non-stop, the P-trap might be missing, incorrectly installed, or drying out. The P-trap is the curved pipe under the drain that holds water and blocks sewer gases. If it’s not installed correctly, nothing stops that odour from drifting straight into your bathroom.
- If you can access underneath the shower, check the drain line to confirm the P-trap actually exists and is fitted correctly.
- Place a square of toilet tissue over the dry shower drain. Flush the nearby toilet. If the paper lifts or moves, air is being pulled through the shower drain, meaning the system may be improperly vented.
- Pour water into the drain to refill the trap and flush the toilet again.
If the water disappears quickly, the trap is being sucked dry and a dry or faulty P-trap allows sewer odours to move freely into the bathroom.
2. Kill Bacteria & Drain Fly Attractants With a Bleach Solution
If the P-trap is fine, the next culprit is bacterial growth or organic sludge inside the drain. Other homeowners tried a 50/50 bleach-and-water solution left overnight.
- Mix bleach and water at 50/50.
- Pour it slowly into the drain.
- Let it sit overnight so it can break down bacteria and biofilm.
Some showers smell because another drain in the house has gone dry. That dry drain allows odours to travel through connected lines and appear in the shower.
- Pour a little bleach water into every drain in the home.
- Flush each one with clean water.
- Make sure EVERY drain has water sitting in its trap.
3. Try Hydrogen Peroxide When Nothing Else Works
Countless cleaning tricks, from natural mixtures to store treatments and even professional intervention, often fail to eliminate a deeply rooted drain smell.
Then they poured hydrogen peroxide down the drain, and:
“It was just GONE.”
Why Hydrogen Peroxide Works
- It kills bacteria deep in the drain line.
- It breaks down organic matter without leaving harsh residue.
- It foams its way into spots other cleaners can’t reach.
Peroxide ends up being the solution when every typical fix barely makes a dent. Once they know their plumbing is set up correctly, peroxide is often what finally gets rid of the persistent odour.
Disclaimer: Stick to common household strengths (around 3%) and use it sparingly, not as a regular maintenance product.
Getting to the Real Source Starts With a Plumber
Plumbers don’t just pour a cleaner down the drain; they run diagnostics to find the exact point where the odour is coming from.
They will be checking the P-trap and venting to make sure they’re not letting sewer gases escape. If something still seems off, they’ll use a CCTV drain camera to look inside the pipes. By then, you can spot cracked sections, biofilm buildup, hairline leaks, or improper pipe slopes that would never be visible from the surface.
If you’re tired of the same odour coming back again and again, calling a plumber is the most reliable way to get your shower smelling clean and fresh again.
Keep the momentum going by reading more helpful homeowner resources on Best Plumbers.
