Composting Toilet

Summary: Advice on installing a compost toilet, how they work, how you maintain them and the advantages of using a composting and waterless toilet on the environment.

How do Composting Toilets work?

Compost toilets turn human waste into compost by biological processes. The western world is now taking up this practice for ecological reasons although it has been in use for many years in the Far East.

In the far east, human waste was highly valued and farmers would actually pay passers by to use their toilets (or equivalent) and use the resulting compost as fertiliser on their land!

The main difference between traditional WC’s and compost toilets is that waste from the former is carried away by water to a treatment works but the waste from a compact toilet is treated in situ at the toilet.

Compost toilets usually consist of two separate containers:

  • The first is used for current toilet use and dealing with waste products there and then
  • The second container deals with the ongoing decomposition process of the waste and contains it until it's at a suitable state that could be considered as completley decomposed

Do they smell?

Despite popular belief, they can be both odourless and hygienic and require only a minimum amount of attention. To fuel the decomposition process and keep odours to a minimum a handful of sawdust and/or peat moss should be thrown into the toilet after use to assist the bacteria do its work.

Human waste contains a high proportion of nitrogen and this would give off ammonia-type smells if straw or saw dust is not added. Toilet paper can also be used because its carbon helps in the process of composting.

Enthusiasts of composting point out that because the waste is treated on site there is a saving in water (using potable water to flush WCs is very eco-unfriendly!), no electric power or bleach cleaning materials are needed and there is less danger of ground contamination as leakage in septic tanks and in sewage treatment works.

Constructing a Composting Toilet

Basic compost toilets can be constructed by competent DIYers quite quickly and easily if instructions are at hand. A good example of these can be seen by visiting the website.

The materials necessary are plywood to create a box (six sides with a hole cut into the hinged top), a toilet seat and a bucket type container with a handle.

Once constructed the box can be painted or tiled but also ensure that your constructed box is as leak proof as possible. You should also have a separate container close to hand to store sawdust, straw and shredded paper that should be added to the toilet after each use.

Make sure you are aware of how to run and maintain your compost toilet before you start as despite being basic in design and in use there are several stages and items that need to be incorporated for the entire system to work correctly. Again, the link above will give you full details on this.

Alternatively, there are ready-made indoor compost toilets on the market in a wide variety of styles. Their costs range from £1,000 to £2,000 depending upon capacity and average number of prospective users. Portable-type external toilets can cost between £1,500 to £2,500 but purpose-made designer toilets (some with thatched roofs!) are more expensive! Some good examples of these can be seen by visiting

You might like to watch a 5 part video on how to set up a compost bin in the garden by going to our Green Living videos section.

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