What type of wood shavings should you use for a composting toilet?

If you’ve been using your composting toilet for a while, you will no doubt have read up about wood shavings for composting toilets, but if you’re new to composting toilets or have recently purchased one, you might be thinking ‘what’s the proper bulking agent to use in a composting toilet?’. 

Like a traditional compost pile, a composting toilet requires a little bit of bulking agent from time to time. This can help your compost reach the right level of heat and density along with introducing natural elements to help the composting process along.  You’ve probably heard all sorts of wives tales about things you can add to a composting toilet and some of them might very well be true, but others can put your composting pile at risk or worse, kill off all the good bacteria in your compost making the composting process stop altogether. 

Not all sawdusts are made the same

If you’ve done some research around composting toilets you’ve no doubt stumbled across the term ‘sawdust toilets’ and people that use sawdust in their composting toilets in your travels around the web, but here’s the kicker – not all sawdusts are created equal.

Some sawdusts are made from treated pine, or other types of woods that have insecticides and other poisons like copper chrome arsenate injected into the wood. This is great if you’re building a retaining wall and don’t want termites or insects to munch on your wood or fungi to grow on it, but if you use sawdust made from these types of wood they WILL KILL the compost pile in your composting toilet. 

Composting toilets work by enabling a series of bacteria, actinobacteria, fungi and moulds to break down all the waste products in your toilet. If you’re adding disinfectants, sprays, chemicals or sawdust injected with any of these items, there’s a good chance you will kill off all these good critters and reduce your compost pile to literally a pile of… well, you get the idea!

What’s safe to use as a bulking agent in a composting toilet?

The best thing to use as a bulking agent is our Plain Wood Shavings as these are guaranteed not to have any pesticides or agents in them that could potentially harm your composting pile. Other people use things like sugar cane mulch, leaves and grass from the garden, wood ash and lime, peat moss, topsoil, hay and straw but it’s imperative that there are no insecticides or poisons in these items that could harm your pile. 

Signs you’ve killed the organisms in your composting toilet 

If you’re experiencing any of the following signs in your composting toilet, there’s a good chance you’ve killed off all the good bacteria in your toilet:-

  • There is a bad smell 
  • The pile isn’t decreasing in size
  • The pile is too wet
  • The pile is cold

The bottom line is if you’re using some type of sawdust or wood shavings in your composting toilet you need to make sure they’re not treated and aren’t going to hurt the organisms in your pile. If you would like to talk with one of our representatives about your composting toilet, please feel free to contact us on 1300 138 182.


Nature Loo / Ecoflo was the first supplier of composting toilets to be certified to New Zealand and Australian Standard 1546.2

Wood Shavings