Clay Filters are Simple Solution for Clean Water

By David SouthDevelopment Challenges, South-South Solutions


Access to clean water is critical to good health. It is a basic human need that when met, leads to the biggest improvements in health and well-being. Dirty water causes diarrhoea (, cholera and typhoid. Diseases caused by dirty drinking water kill almost 5,000 children a day around the world (WHO).

But millions have benefited from a simple solution using clay filters invented and pioneered in Central America, and now manufactured by 28 small factories in 23 countries – the largest in Ghana and Cambodia. Each factory makes up to several thousand filters a day. They offer an ingenious solution that also creates local jobs and skills.

Looking like 30 centimetre-high flowerpots, the filters designed by Guatemalan chemist Fernando Mazariegos blend local clay and plant husks to create a filter capable of killing 98 percent of the contaminants that cause diarrhoea. The husks are burnt away when the filters are fired in a kiln, creating tiny holes that filter out harmful organisms. A coating of colloidal silver ( is painted on the filters after they have been fired in the kiln.

“Each filter can support a family of six,” said Kaira Wagoner, Coordinator of Ceramic Water Filter Projects with the NGO Potters for Peace ( Founded in Nicaragua but now US-based, Potters for Peace has popularized the filters and helps with all the training and support required to establish the workshops and market the filters.

The first filter-making workshop was set up in Managua, Nicaragua after Hurricane Mitch in 1999 ( That workshop has made and distributed 40,000 filters through the Red Cross and NGOs such as Medecins Sans Frontieres/Doctors Without Borders. Potters for Peace has now stopped running workshops and factories themselves, and provides others with the training and advice necessary to produce clay filters.

To work, the filters are placed in a plastic bucket, a spigot added, and a cover put on top to prevent contamination. The filters are capable of filtering four litres of water an hour.

The genius behind the filters is the fact they can be made by small, local workshops – making access to clean water available anywhere, and creating jobs. Just three to four people can produce up to 50 filters a day. According to tests by the Family Foundation of the Americas, a Guatemalan NGO, the filters halve the incidence of diarrhoea in households that use them.

“The cost of establishing a workshop varies largely,” said Wagoner, “depending on the factory’s location, desired production – from 50 per day to 1000 per day – and on the equipment already available in the potter’s workshop. Potters for Peace generally tries to work with potters who already have some of the needed equipment, such as a hammer mill and clay mixer.

“Filters are distributed hand in hand with health and sanitation information which highlights practices such as hand washing,” said Wagoner. “Since many individuals would otherwise boil their water, the filter significantly reduces the time many women would spend gathering firewood. This gives them time for other things such as school and income generating activities, and is better for the environment, especially in locations where problems with deforestation are significant.”

Experience has found marketing is key to the successful adoption of the filters by communities.

“It is very difficult to create a market in a region of poverty,” said Beverly Pillars, also from Potters for Peace, “and to gain acceptance of a new product that the community will want to purchase to keep a workshop sustainable. NGOs may distribute the ceramic water filters, but for the community to fully accept the idea of seeking out clean, safe drinking water on their own, we urge the local owners of the factory to be innovative in marketing.

“Our best approach has been to select partners in developing areas that have some experience such as a potter or brick maker, and help them to find methods that work in their communities to distribute as many of the ceramic water filters as possible, such as a distribution link through local health centres and small corner markets, adds in Yellow Pages, road signs.”

To get a workshop up and running, they need to have a machine to press the clay filters, a kiln to fire them, and a pyrometer ( to measure the temperature of the kiln. It usually takes between three and six weeks of training to become proficient at making the filters. Trainers help with acquiring the proper equipment, building the kiln, the clay filter formula, quality control procedures, and marketing techniques and materials.

“My advice to people wanting to start making filters is to look for local craftspeople to partner with,” said Pillars. “Look at local access to brick, clay and sawdust. Be prepared for hard and rewarding work to bring safe, clean drinking water to developing populations.

“Every location is a best location, because the demand for safe, clean drinking water worldwide is so great. The beauty of the ceramic water filter technology is that it uses very few resources: clay, sawdust or other burnout material available and bricks for a kiln. We have found these resources to be present worldwide.”

The filter has been cited by the United Nations’ Appropriate Technology Handbook, and is used by the International Red Cross and the Nobel Prize winning medical relief organization Doctors Without Borders. There are plans to start more filter factories in Cote d’Ivoire, Bolivia and Somaliland.

Published: December 2008


Development Challenges, South-South Solutions was launched as an e-newsletter in 2006 by UNDP’s South-South Cooperation Unit (now the United Nations Office for South-South Cooperation) based in New York, USA. It led on profiling the rise of the global South as an economic powerhouse and was one of the first regular publications to champion the global South’s innovators, entrepreneurs, and pioneers. It tracked the key trends that are now so profoundly reshaping how development is seen and done. This includes the rapid take-up of mobile phones and information technology in the global South (as profiled in the first issue of magazine Southern Innovator), the move to becoming a majority urban world, a growing global innovator culture, and the plethora of solutions being developed in the global South to tackle its problems and improve living conditions and boost human development. The success of the e-newsletter led to the launch of the magazine Southern Innovator. 

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© David South Consulting 2022

By David South Consulting

David South Consulting is an international development media and consulting service. Designing human development and health. Editor and writer of Southern Innovator.



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