Nazlı Ersoylu · Chemical Engineer · Last updated: October 5, 2026
I am a chemical engineer; knowing how odor molecules behave is part of my job. Even so, when that familiar sewer smell reached me in my own bathroom last month, I did what most people do first: I poured bleach down the drain. The smell left for a few hours and was back the next morning.
Bleach deals with the bacteria of that moment, not with where the odor comes from. My real problem was somewhere else.
Why do a sink and drain smell like a sewer?
- The trap has dried out. The water in the S- or U-shaped pipe under every drain is a plug between sewer gas and your home. In a rarely used bathroom, after a vacation or in summer heat it evaporates and the gas comes straight in.
- A layer has built up in the pipe. Grease, soap residue, hair and food scraps cling to the inside of the pipe. Bacteria breaking this layer down release sulfur gases, and the smell rises each time you use the drain.
- The plumbing has a fault. A blocked vent pipe, a wrongly fitted trap or a cracked pipe makes the odor return again and again. A plumber fixes this one, not cleaning.
What should you do in each situation?
| Situation | What to do | ODORGO product |
|---|---|---|
| Sewer smell after a vacation or in a rarely used bathroom | Pour 1-2 glasses of water into every drain | Spray 250 ml for the air |
| The drain opening and the area around it smell | Clean by hand, then wipe around it | Multi-Purpose Liquid 500 ml |
| The under-sink cabinet smells heavy, or the odor keeps returning | Keep a gel there on a flat spot | Gel 250 g |
| Grease or food odor at the kitchen sink | Clean the strainer; add the liquid to the mop water | Multi-Purpose Liquid 500 ml |
Why are baking soda, vinegar and bleach often not enough?
The foam of baking soda and vinegar loosens part of the soft residue, so it is a useful first step. It cannot lift the whole layer stuck to the pipe, and it does nothing for odor already in the air. Bleach reduces the bacteria for a few days, then the smell returns. Scented drain openers and perfumed sprays only add a stronger smell on top.
How do you remove a sewer smell from a sink step by step?
- Refill the trap. Pour 1-2 glasses of water into every drain in the house, the guest toilet and the balcony floor drain included. If the trap was dry, the odor often stops the same day.
- Clean the drain by hand. Take out the strainer and remove hair and residue. If needed, pour in baking soda and vinegar, wait 15-20 minutes and rinse with hot water, not boiling (around 140-160°F / 60-70°C), so plastic pipes are not damaged.
- Wipe the drain opening. Add 15 mL of ODORGO Multi-Purpose Odor Eliminator Liquid 500 ml to 1 liter of water and wipe the opening, under the sink, the grout lines and around the strainer.
- Clear the air. Shake ODORGO Odor Eliminator Spray 250 ml well and give a few sprays into the air and onto the smelly surfaces, inside the cabinet too.
- Place an ODORGO Odor Eliminator Gel 250 g in the under-sink cabinet or a corner of the bathroom.
The spray is water-based; you can use it on any surface that water does not harm. On water-sensitive fabrics and surfaces (unfinished or untreated wood, silk, leather, electronics, etc.), test on a small hidden area first.
How does the gel keep the odor from settling back?
Bathrooms and kitchens produce odor again every day, so I leave the ongoing part to a passive product. Open the lid of the gel and set it somewhere flat and still; it needs no outlet or batteries. In enclosed areas of up to 15 m² such as an under-sink cabinet it is used for up to 30 days. Do not let the gel or the spray touch food or surfaces that food sits on.
What is in the formula?
ODORGO is a water-based formula built on plant-derived essential oils (pine needle, anise, clove, cedarwood and lime). The oils attract hydrogen sulfide and similar odor molecules, bind them and turn them into odorless compounds. The technology is rooted in research at Delaware State University in the USA.
If the whole bathroom smells, see how to get rid of bathroom and drain odor; for the toilet bowl there is our toilet odor guide.
Keep your bathroom fresh
Frequently Asked Questions
What causes a sewer smell from the sink?
Most often the water in the trap has dried out and sewer gas is leaking in; the second cause is the layer of grease and waste inside the drain pipe.
Does baking soda work on drain odor?
Partly. The foam loosens soft residue, but it does not touch odor that has settled into the air, the cabinet or the tiles.
Is pouring bleach down the drain a good idea?
It is a common but weak method. The odor is back within days, and the fumes irritate the eyes and airways.
Do drain inserts, check valves or scented tablets stop the odor?
Not on their own. The part that blocks sewer air is the water in the trap; an insert is one more spot where hair and soap collect, and most tablets cover the smell with perfume.
When should I call a plumber?
Call one if the odor returns within 1-2 days after you refill the traps and clean, if several drains smell at once, or if there are damp stains on a wall or floor.