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Every year 1.7 million people, mainly children under the age of five, die from diarrhea which is caused by drinking contaminated water. The objective of the Good Foundations International Water Filter Project is to make safe drinking water available by helping set up workshops that use local materials to produce ceramic water filters. These filters are low-tech and low-cost and eliminate approximately 99.88% of water-born disease agents.

Since 1998, Good Foundations International (formally know as Potters for Peace) has been assisting in the production of a low-tech, low-cost, colloidal silver-enhanced ceramic water purifier (CWP) throughout the world and ceramic water purifiers based on the Good Foundations International technology package are now produced at over 50 independent factories in over 30 countries. These filters are the highest-rated product for rural point-of-use water treatment (Smart Disinfection Solutions, 2010).

Here is a short video that explains how the filters work and gives some history:

Good Foundations International does not operate filter-making facilities or sell filters but we train others to do so, and the filter factories that we assist are run as independent businesses owned by organizations or individuals. Good Foundations International receives no financial benefit from the filter producers but GFI filter technicians have their expenses paid and may receive a stipend while working on a new facility.

The Need Is Great

By the year 2015, The UN’s Millennium Development Goal is to cut the proportion of the world's population without sustainable access to safe drinking water by half. The objective of the CWP project is to meet this urgent demand for safe water in rural and marginalized communities by providing technology that can easily be copied by local workshops.

What is Ceramic Water Purifier (CWP)?

A ceramic water filter is a simple, bucket-shaped (11” wide by 10” deep) clay vessel that is made from a mix (by weight) of local terra-cotta clay and sawdust or other combustibles, such as rice husks. The filters are formed by using a press.

The simplest press utilizes a hand-operated hydraulic truck jack and two-piece aluminum mold. Filters are fired to about 860 deg. C. and the milled, screened combustible material burns out, leaving porous clay walls. The filters are tested to make sure they meet a standard rate of filtration and then they are coated with colloidal silver. The combination of fine pore size and the bactericidal properties of colloidal silver produce an effective filter.

When in use, the fired and treated filter is placed in a five-gallon plastic or ceramic receptacle with a lid and faucet. Water passes through the clay filter element at the rate of 1.5 to 2.5 liters per hour.

Pricing for ready-to-use filter units, including the receptacle, is determined by local production costs and is usually between $15 to $25. Replacement clay filters will cost $4 to $6. A basic production facility with three or four workers can produce about fifty filters a day.


The filter design used by GFI was developed in 1981 by Dr. Fernando Mazariegos of the Central American Industrial Research Institute (ICAITI) in Guatemala. The goal was to make bacterially contaminated water safe for the poorest of the poor by developing a low-cost filter that could be fabricated at the community level.

In 1994, the Family Foundation of the Americas (AFA), a Guatemalan organization, became interested in the ceramic water filter when it was found that other strategies were not yielding effective results. Chlorine tablets in rural communities were not well accepted and health complications associated with chlorine misuse caused additional concern. Boiled water wasn’t effective when households failed to boil water long enough to purify it. AFA carried out a one-year follow-up study on the initial Mazariegos-led filter project, and concluded that including this filter in rural health education efforts reduced the incidence of diarrhea in participating households by as much as 50 percent.

In October 1998, Hurricane Mitch tore through Central America. It was one of the most destructive hurricanes ever recorded, and it affected millions of people. Safe water was urgently needed as supply systems (already of borderline capacity and efficiency) had been badly damaged. This prompted Good Foundations International to use the Mazariegos design to begin a Ceramic Water Filter production workshop in Nicaragua.
In the first six months over 5000 filters were distributed through non-governmental organizations. The workshop, called Filtron, evolved into a worker-owned cooperative and is now incorporated as a privately-owned business.

Good Foundations International has since provided consultation and training to set up production facilities in Guatemala, Honduras, Mexico, Cambodia, Bangladesh, Ghana, El Salvador, the Darfur region of Sudan, Kenya, Benin, Yemen, Nigeria, Tanzania, Peru, Somaliland and other countries.

The CWP has been cited by the United Nations’ Appropriate Technology Handbook, and hundreds of thousands of filters have been distributed worldwide by organizations such as the International Federation of the Red Cross and Red Crescent, Doctors Without Borders, UNICEF, Plan International, Project Concern International, Oxfam and USAID. We have also financed or assisted in laboratory testing and field studies of the filter with various institutions, among them MIT, Tulane University, University of Colorado and University of North Carolina. Good Foundations Internationalis a member of the World Health Organization’s International Network to Promote Household Water Treatment and Safe Storage.

Partnering with GFI

Organizations interested in initiating a filter project should contact GFI to begin the conversation. If GFI finds that an organization can demonstrate its ability to meet GFI’s project guidelines, a GFI technician will be assigned to the project and will assist with setting up the factory and training local workers. An on-site visit of at least four weeks is necessary and the cost of start-up varies according to what resources are needed. An integral part of GFI’s filter technology is a fuel-efficient kiln.

A functioning CWP facility becomes part of an ongoing intra-organizational filter dialogue, staying abreast of all related research and developments through email and follow-up visits. GFI-sponsored filter projects are designed to provide profitable and sustainable employment and the local retail price of a CWP is set so as to maintain its accessibility to the poor while providing a decent wage for the workers.

Education, health training and follow-up are critical to the successful introduction of the CWP into rural communities. Good Foundations International has developed brochures, decals and a manual of procedures in several languages.

The Good Foundations International Approach

The Good Foundations International ceramic filter technology is a process involving machinery and substantial infrastructure. With years of experience we have found this is the only way to produce filters of consistent quality. We are often approached by potential partners who are looking for an artisan approach to filter making, i.e. a simple hand formed filter, fired without a proper kiln. This is not what we are offering, as far as we know such a thing does not exist and functional ceramic water filters cannot be produced in this manner. Before contacting Good Foundations International please read through some of the documents in the “Getting Started” sub-page so as to have a clear idea about our technology.

Water Treatment Options

PFP’s CWP is one of several currently accepted low-tech, inexpensive, point-of-use water purifying options. Each has strong and weak points and ideally a community should choose what is appropriate for its own situation.

Open Source

In an effort to share and develop CWP technology on a global scale, PFP’s ongoing development of the CWP uses the Open Source Manufacturing model. We do not hold a patent on the CWP and the technology is available to anyone. It is hoped that all parties will share findings from research and development with GFIand the wider community in an effort to expedite the availability of the CWP to those in need. The technology recommended by GFI continues to be subjected to extensive testing and all potential projects must meet guidelines established by GFI. Good Foundations International assumes no responsibility for CWP projects undertaken without the approval of the GFI Board of Directors and Filter Committee.


The ceramic water filter technology has been and continues to be extensively tested. On the “Research” sub-page there is a document compiled by Barbara Donachy which serves as a quick reference, summary and review of more than 70 of these studies.

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