It's the question we get asked most often: do composting toilets smell? With the right system, correctly installed and looked after, you should be able to use your bathroom without persistent toilet odour.
The answer? Your bathroom should not smell.
If you're imagining a long-drop, you're not alone. That “stinkma” has followed composting toilets around for years! But a purpose-designed composting toilet is quite different from an unventilated pit or an improvised container. Keeping odour out of your bathroom is part of its design.
Two things do most of the work: composting with oxygen, and ventilation that takes air away from the room.
Aerobic composting makes the difference
A healthy compost pile needs oxygen. The right bulking material, moisture balance and enough chamber space help keep air moving through it. That avoids the stagnant, oxygen-poor conditions that can produce strong decomposition smells.
You may notice a smell when you open a chamber to service it. That's different from having an unpleasant smell in the bathroom during everyday use. The toilet is designed to keep that room comfortable while the material is contained and treated.
Ventilation takes the air in the right direction
Many systems use a fan that runs continuously, drawing air through the pedestal or chamber and out through the vent. Some are designed for passive ventilation instead. Check which arrangement your model requires—one isn't automatically a substitute for the other.
Where the vent goes matters. Your roof shape, nearby windows, surrounding buildings and shelter from the wind can all affect airflow, as can other extractor fans in the house. Sound connections and enough replacement air help the system work properly. Have the vent installed to the model's requirements and the site design, rather than relying on one roof-clearance figure for every property.
You should not have to put up with a persistently smelly bathroom simply because you have chosen a composting toilet.
What if an odour appears?
If you do notice an odour, start with the simple checks. Is the required fan running? Is the vent clear? Are the seals in place? Has the toilet had more use than usual? Then check moisture, drainage where fitted and whether you're using the right amount of bulking material.
Our guide to troubleshooting a composting toilet generating odour takes you through those checks. Finding the cause is more useful than repeatedly trying to cover the smell.
You can have a composting toilet and a pleasant indoor bathroom. Choose a system that suits your use, keep up its normal care routine and get help if something changes. Persistent odour isn't something you should have to accept.
Noticing a smell that was not there before?
Call WCTNZ® on 0800 022 027 with your toilet model and a description of what has changed. We can help you work through the likely causes.
