Composting Toilets
People have various opinions about composting toilets. Many disregard them due to concerns relating to odour, maintenance, or appearance. However, I have lived with one for many years and can say with certainty that these concerns are easily managed and life with a composting toilet is perfectly comfortable and practical. In fact, composting toilets are a great option for reducing your dependence on utility water, reducing demand on your rainwater harvesting system, or for avoiding the construction impact and cost of a conventional septic system.
If we assume the average person flushes 35 times per week and uses 11 litres per flush (standard toilet, not dual-flush), a household of 4 would use 1.5 kL per week, or 80 kL per year, just flushing the toilet! Clearly a great option for reducing your water usage.
Compositing toilets are treated differently by different local government areas and it is important to check what the rules are in your area before installing a composting toilet.
What are Composting Toilets?
Composting toilets are waterless systems that take advantage of organic decomposition to breakdown human waste. Over time, and with a small addition of a carbon rich cover material, it becomes indistinguishable from a healthy garden compost. With a well-designed system, considering oxygenation, temperature, drainage, and carbon additions, the composting process enables aerobic bacteria to do its work surprisingly quickly. An excellent, nutrient rich compost is produced for your garden.
There are many different composting toilet systems and designs. Proprietary systems can be purchased and installed easily. Alternatively, they can be designed and built using simple principles and common materials.
Recently, they have become a popular option for tiny homes, remote houses, those living off the grid, boats, campervans or RVs.
Advantages of Composting Toilets
- Composting toilets are an excellent solution for properties that do not have septic systems (onsite disposal), or when a utility provided sewer connection is not available.
- Composting toilets are ideal for properties that source water on-site, for example rainwater harvesting, and therefore need to minimise water usage.
- Toilets typically represent the single highest use of water in the house. In some homes this can be 25% or more of the total water consumption. Composting toilets do not require any water to operate which means all of this water will be saved. Occasional cleaning water is all that is required.

Disadvantages of Composting Toilets
As described above, there are many perceived negatives with composting toilets, that are in reality not a concern. Careful design and attention to their operation can easily prevent issues getting out of hand.
- The system lacks oxygen and becomes anaerobic, odour can become an issue. Many composting toilet designs incorporate a venting system with a small fan (5 watt, 12 volt for example) that pulls air through the compost and vents it high enough above the building for it not to be of concern. Such a system can be designed so that the toilet pedestal is under negative pressure, causing airflow away out of the vent, rather than into the room.
- Some people are not enamoured by the appearance of composting toilets. Images of dusty, dirty ‘long-drop’ toilets where the user can see both their own deposits, and those of the people before them. However, in reality this does not need to be the case. There are many clever designs that look modern and clean in any house and can be easily managed without compromising style. Proprietary products have come along way in this space.
- Maintenance, and the handling of ‘dirty’ material is seen as a significant drawback for many people. And it is true, a composting toilet takes more looking after than a conventional flushing toilet. They must be cleaned periodically, the compost needs to be removed and disposed of, and the toilet reset. You may also need to ensure cover material is always available in the toilet. These all become routine tasks easily managed with no fuss.

A Final Thought...
Composting toilets are a great option for those who want to reduce their water usage and dependence on the utility supply. They can be purchased in many different designs and sizes, or they can be built at home to suit your needs with simple materials and basic knowledge. They will easily integrate into your lifestyle and you too will become an advocate, changing the perceptions of your friends and family when they visit the toilet at your house.
Learn more in our in-depth article on the subject, How Do Composting Toilets Work?
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