By Jasman, Co-founder of PureZest | Updated October 2026 | 8-minute read

If you've ever stepped into the shower and caught a whiff of rotten eggs or sewage, you're not alone. So, why does my shower drain smell? In most homes, it's one of three things: a slimy buildup of hair, soap scum and body oils inside the drain, a dried-out P-trap letting sewer gas through, or a slow clog. The good news is that most of these are easy to fix yourself in under 30 minutes.

Key Takeaways

• The #1 cause is buildup: hair, soap scum and body oils collect in the drain and break down, creating a musty or rotten-egg smell.
• A sewage smell often means a dry P-trap: in a guest or basement bathroom that rarely gets used, the water seal evaporates. Running the shower for a minute usually fixes it.
• Clean the drain cover and the top of the pipe: remove the grate, pull out hair, scrub away the slimy film, and rinse with hot (not boiling) water.
• Skip the bleach-and-vinegar combos: never mix bleach with acids or ammonia. It creates dangerous gases and doesn't remove the buildup that causes odours.
• If the smell keeps coming back after cleaning and refilling the trap, call a plumber. It may be a venting or sewer line issue.

Why Does My Shower Drain Smell?

Your shower drain smells because organic gunk (hair, soap scum, skin cells and body oils) builds up inside it and starts to break down, or because sewer gas is escaping through a dry or faulty trap. The type of smell is a big clue to the cause.

Here's a quick way to diagnose it:

• Musty, mildewy or "dirty sock" smell: buildup (biofilm) on the drain cover and upper pipe.
• Rotten eggs or sulphur: decomposing gunk in the drain, or occasionally sulphur in your water (more common with rural well water).
• Sewage smell: sewer gas getting past a dry P-trap, a broken seal, or a blocked plumbing vent.
• Smell plus slow draining: a partial clog that's trapping hair and soap scum.

Under your drain is a U-shaped pipe called a P-trap. Its small pool of water blocks sewer gas from entering your bathroom. As EPCOR, Edmonton's water utility, explains, a dried-out P-trap is a common reason for sewer odours in a home, and pouring water down the drain is a possible fix.

What You'll Need

• Rubber gloves
• A screwdriver (if your drain cover is screwed in)
• A plastic drain hair snake or zip-tie tool (sold at most Canadian hardware stores)
• An old toothbrush or small drain brush
• PureZest Bathroom Cleaner (enzyme + citric acid formula)
• A microfibre cloth
• A kettle or pot of hot tap water (not boiling, especially with PVC pipes)

How to Get Rid of Shower Drain Smell (Step by Step)

To get rid of shower drain smell, remove the hair and slimy film from the drain cover and top of the pipe, scrub with an enzyme cleaner, then flush with hot water. The smell usually lives just under the cover.

1. Remove the drain cover. Pop it off or unscrew it. You'll likely see a ring of grey or black slime and a mat of hair.
2. Pull out the hair. Use a plastic drain snake to hook out hair from the first 15 to 30 cm of pipe. Bag it and toss it in the garbage (never flush it).
3. Spray the cover and drain opening. Spray PureZest Bathroom Cleaner generously on the cover, the drain flange and as far down the opening as you can reach.
4. Wait 1 to 2 minutes. This gives the bio-enzymes time to break down soap scum and body oils, and the citric acid time to loosen hard water deposits.
5. Scrub. Use an old toothbrush to scrub the cover, the underside of the grate and the inside of the pipe opening.
6. Flush with hot water. Pour a kettle of hot tap water slowly down the drain, then run the shower for a minute to refill the P-trap.
7. Replace the cover and wipe dry with a microfibre cloth.

Shower Drain Smells Like Rotten Eggs: What to Do

A rotten-egg smell from a shower drain is usually decomposing hair and soap scum, so start with the deep-clean steps above. If the drain is clean and the smell is still there, check your water.

• Run the cold tap, then the hot tap in another sink. If only the hot water smells, have a plumber check your water heater.
• If all your water smells and you're on a private well (common in rural BC and Ontario cottage country), ask your local health authority about water testing.

Shower Drain Smells Like Sewage: Check the P-Trap

A sewage smell usually means sewer gas is getting past the P-trap, often because the water in it has evaporated. This is especially common in basement showers, guest bathrooms and cottages that sit unused for weeks.

1. Run the shower for 30 to 60 seconds to refill the trap.
2. For bathrooms you rarely use, run the water once a week or so, especially during dry Canadian winters when indoor heating speeds up evaporation.

If the trap is full and you still smell sewage, the problem could be a cracked pipe, a failed drain seal, or a blocked roof vent. That's a job for a licensed plumber.

Shower Drain Smells Musty or Like Mildew

A musty smell usually comes from damp buildup around the drain and on nearby grout, not deep in the pipes. Humid bathrooms keep that film growing.

• Check nearby grout lines too. Our guide on how to clean shower grout covers black and orange grout around drains.
• Run your bathroom fan during and for 20 to 30 minutes after every shower.
• Spot pink slime near the drain? Read our post on pink "mould" in the shower to understand what it is and how to keep it from coming back.

What NOT to Do

• Never mix bleach with vinegar, other acids or ammonia. These combinations release toxic gases, and it's easy to do by accident when you're pouring products down the same drain.
• Don't rely on bleach to fix the smell. It may mask the odour briefly, but it doesn't remove the hair and soap scum that cause the problem.
• Avoid boiling water in PVC drains. Hot tap water is enough.
• Be cautious with harsh chemical drain openers. They can damage older pipes and septic systems. For a full clog, call a plumber.
• Test first on special finishes like brushed brass or matte black drain covers, using a small hidden spot.

How to Prevent Shower Drain Smell (and How Often to Clean)

The easiest way to prevent shower drain smell is to stop hair and soap scum from building up in the first place. A few small habits make a big difference.

• Use a hair catcher over the drain and empty it after every few showers.
• Clean the drain cover weekly when you clean the rest of the shower.
• Deep-clean the drain monthly using the step-by-step method above.
• Tackle soap scum on walls and glass too. It all washes toward the drain. See our guide on removing soap scum from shower glass doors.

In hard water areas like the Prairies and southern Ontario, mineral deposits give gunk more places to cling. For spots around your drain and fixtures, see how to remove hard water stains.

Why We Made PureZest Bathroom Cleaner for Exactly This Kind of Buildup

When I ran a cleaning services business, the cause of smelly showers was almost always the same: soap scum and body oils that harsh sprays just slid over. That's why we built our Bathroom Cleaner with a double-action formula.

• Bio-enzymes digest soap scum and body oils, the organic film that causes musty drain smells.
• Citric acid dissolves limescale and hard water deposits on drain covers, faucets and glass.
• Coconut-based foam clings to tile, glass and drain flanges instead of running straight off.
• A fresh scent from peppermint oil and lemon derivatives, with no bleach and no ammonia.
• Septic-safe and won't bleach coloured grout.
• Simple to use: spray, wait 1 to 2 minutes, scrub, rinse.

Customers tell us that after switching, they've gone from cleaning their tubs and tiles every week to every 10 to 15 days, thanks to the longer-lasting clean.

Want to stock up? Grab the 2L Bathroom Cleaner refill to reduce plastic, or try the full Natural Enzyme Bathroom Set. Curious how enzymes work? Read what an enzyme cleaner is.

Shop PureZest Bathroom Cleaner

Frequently Asked Questions

Why does my shower drain smell like rotten eggs?

Most often, it's hair, soap scum and body oils breaking down inside the drain. Clean the drain cover and top of the pipe, then flush with hot water. If only your hot water smells, have a plumber check your water heater.

Why does my shower drain smell like sewage?

A sewage smell usually means the P-trap has dried out and sewer gas is coming through. Run the shower for a minute to refill it. If the smell persists, a plumber should check for a cracked pipe, bad seal or blocked vent.

How do I get rid of the smell in my shower drain?

Remove the drain cover, pull out trapped hair, spray an enzyme bathroom cleaner on the cover and drain opening, wait 1 to 2 minutes, scrub and rinse with hot water. Then run the shower briefly to refill the trap.

Can a smelly shower drain make you sick?

A musty drain is mostly an unpleasant nuisance, but a strong, persistent sewage smell shouldn't be ignored. Ventilate the room and have a licensed plumber inspect your plumbing if the smell continues after cleaning and refilling the trap.

Is baking soda and vinegar good for a smelly shower drain?

The fizzing can loosen a little surface gunk, but it doesn't remove hair or do much for heavy soap scum. Physically removing hair and scrubbing the drain with an enzyme cleaner is more effective. Never combine vinegar with bleach.

The Bottom Line

A smelly shower drain is almost always built-up hair and soap scum, or a dry P-trap. Clean the drain opening, flush with hot water, keep the trap full, and stay on top of soap scum weekly. If the smell won't quit, call a plumber.

Ready to tackle it? Try PureZest Bathroom Cleaner for a drain, tub and shower that stay fresher for longer.

About the author: Jasman is the co-founder of PureZest, a BC-based natural cleaning brand, and previously ran a cleaning services business.