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In this post I’ll give an overview of composting toilets, their pros and cons and how they work. It’s a good idea to read the entire section before you start to build your own composting toilet. It’s not hard to build your own but you need to get a good understanding of their operating principles.

There are detailed descriptions and diagrams you can use as a reference, along with photos I’m adding as I review and update the site.

Before I describe the composting toilet system I built, some background information on composting toilets is needed. In short, if you don’t take the time to get a good understanding of composting toilet principles, you can’t expect them to work efficiently nor safely and you’ll end up with (literally) a big mess!

Why have a composting toilet?
There are many reasons to have one and probably just as many reasons not to. Maybe it would be easier if I discuss my own reasons.

I chose to build my own composting loo because -

• I own an empty section in a reasonably remote country village. The village is not large enough in terms of population to support a typical reticulated sewer system operated by local authority or commercial enterprise
• I needed something that had very low running costs and could be left for long periods of time in-between visits to the property
• I wanted to use something other than the typically used anaerobic toilet system or septic tank
• I couldn’t afford to purchase a commercial composting toilet or the installation of a septic tank system
• I have a “green” or “eco-friendly” way of looking at things – I feel guilty every time I flush a traditional toilet – what a waste of water! The “flush and forget” mentality doesn’t sit too well with me.
• I like to build things and challenge myself!!

How do they work?
Microbes! Simply do your usual “business”, use toilet paper as you would normally, although it pays to use a brand of toilet paper that isn’t bleached and laden with chemicals and fragrances. We’ll talk about this later. Add a handful of special material when you’re finished. There are a number of different materials that can be added. Garden soil is good material to use as a “starter” or from time-to-time as it contains “zillions” of microbes. Other materials to use include: peat, wood shavings and sawdust (non-treated), fine bark chips, popped popcorn, shredded paper, dried grass clippings, and of course the toilet paper you add during normal use. These materials assist the composting process by allowing air to penetrate. I’ll talk about this in more detail later.

What are they like to use?
Probably the strangest thing I noticed when I first used mine, was, having done my “business” I’d stand up and automatically put my hand out to “flush”, only to realize you don’t flush!! It took a while to get used to that. Do they smell? Surprisingly, no! Certainly not in an unpleasant way. When you lift the lid you might smell a faint rich-soil smell. This is totally normal and how they should be.

Maintenance
The amount of maintenance needed depends on many factors;

• the number of people using the system
• how often the system is used
• the design of the system
• the air temperature / climate / season etc.

I find that for my system with 2-3 adults using it every second weekend, there is virtually no maintenance. In summer, I sometimes add a little water if it looks like things are drying out a bit too quickly and every three-four months I use a special “paddle” to turn the compost over a little, just to help aerate things. No mess, no smell, maintenance is easy! I built my system at the beginning of 2009 and at some stage I may have to remove the inner plastic lining, tie the top and leave it to sit in a warm position over summer to ensure any pathogens are truly “cooked” before burying the contents and starting again. Given that the system is used infrequently, I’m guessing I may never need to do this.

Advantages and Disadvantages of Composting Toilets?
On the down side: you have to get familiar with the whole concept of how they work, you need to spend time planning, you have to spend time building it and sourcing materials. There are of course legal issues and local authority regulations and you need to decide if you want to do things properly and get approval, which could be a complicated process depending where you live. There are also possible health issues if you design it incorrectly and get it really wrong!

On the up side: save money – mine was built mainly from existing or re-cycled / cheap materials. Total cost was about $150 – $200. You feel like you’re doing your bit for the environment. Building you own composting loo is a rewarding DIY project. You will be saving huge amounts of water and doing your bit for the environment.

Is it possible to build your own?
If you’re reasonably handy, YES! If changing a light-bulb is as handy as you get, you might be better to get assistance or look at some of the commercial composting systems available. Electric toilets as used in boats and RV / campers are another option. Of course, you can go down the anaerobic route and purchase one of the many “self-contained closed-tank” chemical toilet systems, but depending on design you may be faced with having to empty the tank and then there’s the possible harmful impact on the environment and cost of adding / using chemicals.

Composting Toilet Do’s and Don’ts!
Do’s

• add some suitable material each time you use it
• decide whether you want to get your local authorities involved or keep it hush
• as mentioned elsewhere in this post, understand how they work – I can’t stress this enough. Take time to plan
• do your research – read all pages of this site before you start building it.  There are plenty of other sites about this topic out there too!
• educate the people who will use it – make sure they understand how to use it and know not to use chemicals etc
• monitor the compost carefully. As the system is an organic living thing, it is your responsibility to keep a close eye on the condition of the compost e.g. add more water if it’s drying too quickly, reduce the airflow, add more heat etc

Don’ts

• do not use chemicals! These will kill the microbes in the compost
• do not rush into the building phase – plan it carefully first
• do not put anything down the composting loo that won’t decompose e.g. plastic wrappers from ladies’ personal hygiene products