Composting Toilets

If managed correctly, composting toilets are generally better for the environment, and there are no restrictions in relation to soil type and groundwater.  They are also your cheapest option, though they do require power, they can be hard work and, if not maintained correctly, can be a health hazard. One of the biggest issues here is the wet – it is very difficult to dry out the compost during the wet season, and it will be bad for the environment, very unpleasant for you and a health risk to you and your neighbours to bury it wet. Research this option to be sure you are ready for the commitment before deciding on a composting toilet, and make sure the model you choose has been proven to work in a tropical environment.

Composting toilet

Composting toilet

  • They require no digging and produce no wastewater – dry compost can be spread on the garden like ordinary compost.  
  • They come in many shapes and sizes, but they are all more hands-on than the septic or wastewater plants.
  • They do not use water, saving a household up to 80,000L per year.
  • You will also need a grey water system to process wastewater from the kitchen, laundry and bathroom. Both innovation and Local Government policy has shifted a long way in respect to grey water management such as reed bed systems. Check with Douglas Shire Council for their interpretation in this form of management
  • Be very selective – some systems operate better here than others.  Try to find someone else with the same system and ask to see it.
  • A larger surface area on the compost bin will provide better evaporation.
  • Most systems require a fan to evaporate moisture and a heater.  You will need to take this into account when assessing your power generation needs and capabilities, particularly during the wet season when the fan will need to run constantly.  Some systems contain a heater, while others use heat generated elsewhere, such as the roof or the fridge. Power consumption estimates in the product manuals may not be accurate for this climate due extended drying times.
Composting toilet

Composting toilet


  • Location will also have an impact on evaporation – a good breeze can aid the fan.
  • If you are getting a worm-farm model, you should cook the compost prior to emptying it.  Unlike native worms, composting worms come to the surface to eat leaves and other forest debris, increasing the nutrient content of the typically low-nutrient rainforest soil, making it unsuitable for some vegetation. They will also compete with native worms.  
  • The compost bin needs to be above ground, so the toilet will need to be elevated, some more than others.  If possible, consider this in the design of your house.
  • MAINTENANCE: all composting toilets require the solids to be removed periodically, the frequency depending on the system and use.  There is no service to do this, so you will have to do it yourself.  You will require power, particularly in the wet season.  Fans and heaters will require some maintenance and quality can vary significantly depending on the system.