Compost toilets have been slow to catch on in the UK, but will become increasingly attractive as the price of mains water continues to rise. They should never smell, so they don’t have to be outdoors.

Everybody makes manure, and it’s a fact of life that having made some, you naturally want to get away from the smell. Using water to carry the waste away is an obvious solution. So obvious, in fact, that the first known example was in the 31st century BC at Skara Brae in the Orkneys. However, there are some obvious problems with using water.

  • Water is a finite resource. The UK has been slower than most countries to adopt compulsory metering of mains water, but it’s coming; 80% coverage is forecast by 2020. Quite aside from environmental concerns, flushing the loo is going to cost you more money every year as the price of energy rises.
  • Poo pollutes. Whatever the source of your flush water, dropping human waste into it renders it useless. It has to be cleaned up or disposed of safely; hence the sewerage charge on your utility bill, or your septic tank costs.
  • Nutrient loss. Each of us produces around 450kg of manure every year. Human manure is just as valuable as any other kind of animal manure, so why throw it away?compost toilet

Don’t compost toilets smell?

A properly-designed compost loo doesn’t smell at all, although the simplest self-build types sometimes smell pleasantly of the sawdust ‘soak’ material. Because of this they don’t have to be outside, making them just as comfortable as a regular WC.

Are composting toilets legal in the UK?

Although compost toilets are still unusual in the UK, there is nothing in law prohibiting their use. As with installing any sanitary system, you should inform the Planning Dept and Environmental Health Officer of your local authority, and the Environment Agency (or SEPA in Scotland). They may or may not be familiar with what you’re planning, so be as honest and open as possible. If you are using a commercial system, the suppliers are used to providing information to local authorities and will be happy to help you with this process.

Are compost toilets safe?

The fresh compost produced from a compost toilet is very similar in smell and appearance to regular compost. However, because of the risk of human pathogens it has to be aged for longer before it is safe to use on your plot. The length of this ageing process depends on the design of the composting system. Commercial systems that are designed to compost ‘hot’ only require two or three years of ageing, whereas simple self-build designs need longer.

How much does a compost loo cost?

You can expect a commercial compost toilet system to cost between £400 and £2000, depending on what sort of system you are looking for. Self-build is also an option to keep costs down, but do your research properly and don’t skimp on the materials.

Over the coming months, Farm In My Pocket will be featuring articles on both commercial and self-build composting systems to demystify the subject.

Some attractive examples of compost loos from Permaculture Magazine

The Humanure Handbook. FREE to read online or as an e-book!
Image courtesy of redjar on Flickr

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