This site is about vermicomposting flush toilets – on-site processing of domestic sewage with worms. These aren’t the first vermicomposting sewage systems by any means, but they’re the first (to our knowledge) to be based on open source principles with non-proprietary technology and low cost components, many of which can be sourced from existing waste streams.

The method was designed and pioneered by Anna Edey in the USA in the mid 1990s and modified by Wendy Howard in Portugal 20 years later. Wendy constructed a simplified version of Anna’s system on her farm and, together with local architect Vera Filipa Rocha, introduced her local municipality to the concept. These toilets are now being installed and retrofitted in Central Portugal and beyond, with the first municipally-constructed system commissioned in the village of Pai das Donas in July 2016.

Wendy Howard's vermicomposting toilet system in Central Portugal

Wendy Howard’s vermicomposting toilet system in Central Portugal

The beauty of the system is in its straightforward simplicity, which it achieves without compromising the ecological principles which govern its function. It needs no external energy input or machinery. It’s proved itself over 20 years of trouble-free use where more complex and expensive proprietary technology has sometimes failed.

Unlike most other low tech DIY methods of composting human waste, it allows for the use of conventional flush toilets. This removes the principle objection many people have to composting toilets. Potentially it could encourage greater decentralisation of sewage processing, taking pressure off overloaded municipal facilities and transforming human waste from an environmental pollutant into a valuable resource.

Technologically, it’s no more complex and much more efficient than a traditional septic tank system and, where local regulations permit, can easily be installed and maintained by any competent DIYer. Maintenance and use requires less effort than many dry composting methods and the system is odour-free.

On this site you can learn about the science behind processing human waste with worms, how the system works, its history, full construction details and the maintenance involved. You can study details of working installations, find out when and where you can attend workshops and ask questions in the forums. In time, we hope to publish a directory of working installations open to visitors.


Please note: The information on this site is offered in good faith as is. It’s based on community-sourced experiences of installing and operating this or similar models of a household-scale vermicomposting flush toilet system. It’s intended to encourage others to take responsibility for the ecological implications of their household waste disposal and to design and develop their own vermicomposting toilet systems. Since no two installations are the same, we can offer no guarantees and the information on this site is no substitute for an intelligent assessment of the unique challenges of each individual location, many of which we may not have foreseen in setting out these guidelines. If you don’t feel competent to make this assessment for yourself, please seek help, either on the forums on this site or from a local professional with appropriate knowledge. Although we will do our best to help you sort out any problems, we accept no responsibility for how you chose to implement a system based on the information here. Advising on compliance with local codes outside our locality and country is not possible.

Wendy Howard and Vera Filipa Rocha, November 2016


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