How often do you have to empty a composting toilet?

If you’ve been thinking about purchasing a composting toilet, chances are you have many different questions about how they work, what you can put in them, what to do when you have diarrhea and how often you need to empty them.

We realise when you first start thinking about purchasing a composting toilet you probably have mental images of pouring a ghastly smelling slop into a container with a peg on your nose and full protective gear. Nothing could be further from the truth and once people start getting over their ‘poophobia’ they realise the end product of a composting toilet is very similar to topsoil in smell and feel. 

Given that the end result of a composting toilet is very much like topsoil, people still wonder how often a composting toilet needs to be emptied. The answer to this question, like many questions in life is, it depends. In saying that, for the sake of throwing out a number, on average you can expect to empty your composting toilet every three months or so.

Different composting toilet types will require emptying at different rates

So there are a few things that will impact on the frequency in which you have to empty your composting toilet. These are:-

  • The size of your family
  • The size of your family’s, well, you know… bum slugs
  • The size of your composting toilet chamber
  • How often the unit is used (family loo or holiday home, etc)
  • They type of unit you have (split system or self contained)

Let’s run through each of these in order. 

The size of your family will impact on how often you will need to empty your composting toilet

This kind of goes without saying, but the more members of your household use your composting toilet, the quicker it will reach capacity. Most homes in Australia have between 2-3 people in them (if we were to get technical, the average family size is 2.53) and for most families of this size, a self contained toilet like the Clivus Multrum™ CM2 used as your only family toilet will require emptying roughly every 1-2 months.

If your family went with a slightly larger unit like the Nature Loo™ Classic 850 or the Clivus Multrum™ High Profile you could expect to empty this every 3-5 months or so, depending on usage. 

If you're looking for a 'set and forget' type of arrangement where you set up your composting toilet and only have to think about emptying it once or twice a year, we highly recommend looking at some of our larger units like the Clivus Multrum™ CM8 or the Clivus Multrum™ CM14. These larger units will allow for several months of usage before you need to empty the unit. 

Obviously if you have a large family, these timeframes will differ. 

The size of your composting toilet chamber will change emptying frequency

If we look at the models we’ve already listed in this article we can see there’s some considerable variation in chamber sizes. Let’s take a look at these models along with some of our most popular toilets:-

  • Clivus Multrum™ CM2 = 32L chamber
  • Clivus Multrum™ Low Profile = 80L chamber
  • Nature Loo™ Classic 850 = 120L chamber
  • Clivus Multrum™ High Profile = 120L chamber
  • Clivus Multrum™ CM8 = 850L chamber (set & forget)
  • Clivus Multrum™ CM14 = 1400L chamber (set & forget)

 

As you can see there’s a big difference in chamber sizes and this will impact on how often you need to empty your composting toilet. 

It’s worth noting that many of our self contained systems come with an additional chamber so you’re able to simply swap out a full container for an empty chamber and let the full one cure for a couple of months before you need to empty it. This will give the compost time to fully break down and resemble a topsoil-like end product. 

Now, because we understand you don’t want it in your search history, we’ve taken the liberty of researching how big the average poo is. Most people will poop an average of 400-500 grams when they’re busting a grumpy. Now that you have that fascinating piece of information, it’s up to you to then do the calculations on how quickly that would fill up the chambers listed above (we can’t do everything for you!!!).

The type of composting toilet you have will change the frequency in which you need to empty it

Generally speaking, split system composting toilets can hold a lot more waste than self contained units. Split systems typically have a larger chamber in which to store waste but they do require more space and an area under your home where the chamber can be stored. Self contained composting toilets are great for homes with limited space or have been built on a concrete slab. 

So as you can see, there’s a lot more that goes into a composting toilet than what comes out of you. Size of your family, size of the unit and the type of unit all play an important part in how often you would need to empty your composting toilet.