Q: What is a Colloidal Silver Impregnated Ceramic Water Filter (CWF)?

A: A simple clay filter, incorporating the microbiological inhibiting properties of colloidal silver. Ceramic Water Filters are devices that can be made by local potters and sold cheaply to people in rural areas. The filters remove bacteria including E-Coli and vibrio-cholera, as well as giardia, streptococcus, total coliforms and cryptosporidium. With proper cleaning, maintenance, and monitoring this filter technology can provide potable water for families that draw their water from unreliable sources.(springs, rivers, or wells)


Q: How does the Ceramic Water Filter work?

A: The clay filter element is set in a clay or plastic receptacle, which protects the filter element from damage and stores the purified water. One pours dirty contaminated water into the filter and the water filters down through the tiny microscopic pores in the clay. The pore size is made larger with the addition of an organic burnout material (sawdust, rice husk), which allows the water to flow through at a rate of 2 to 3 liters an hour sufficient drinking water for a family of four for a day.


Q: How long does the Ceramic Water Filter last?

A: This question depends on many factors. How clean the water being poured into the filter is the main one. If the the water appears muddy then the filter will not last long unless proper care is taken. If the water is prescreened through a cloth to eliminate the dirt and debris then the less dirt going into the filter the better. We say the filters are guaranteed for 2 years but lasts with care much longer.


Q: What bacteria does the filter elliminate?

A: The filters remove bacteria including e-coli and vibrio-cholera as well as giardia, streptococcus, total coli forms and cryptosporidium.


Q: Who originally developed the Ceramic Water Filter?

A: The concept of an open source ceramic water filter was developed in Guatemala in 1981 by Dr. Fernando Mazariegos of the Central American Industrial Research Institute.  The original concept was of a hand made filter.  Our late technical coordinator Ron Rivera developed the technology by adapting simple molds and presses to form cast the filter’s shape.


Q. How do I care for my Ceramic Water Filter?

A. When you first get your CWF you should sterilize the receiving vessel, a little bleach and lots of water will do. If your water is very muddy run it through a cloth to remove dirt and leaves etc. run the water through the filter once and throw the initial water out and add water for the second time. Keep the lid on the filter at all times and do not touch the tap where the water comes out as bacteria on your hands (especially when you have not washed them) will contaminate the water.


Q: Can they be cleaned of the bacteria that collects on them?

A: Filters must be cleaned regularly with mild bleach solution, and a soft brush. Proper handling is required to prevent accidental re-contamination. (See Above: How do I care for my Ceramic Water Filter?)


Q: What is required to set up a filter factory in a community?

A: A basic filter factory is able to produce 100 filters per day. Costs involved in developing a factory vary significantly because of the vast variability of conditions in the field. 

-Reliable sources of clay, burnout material, and other inputs must be available.

-Appropriate land and buildings must be acquired.

-A kiln is built, the design depending on available local materials, fuels and capacity.

-Factory equipment is purchased or built, local conditions determine what level of technology is appropriate, this is dependent of energy sources and local skill resources. Electricity is not a necessity in the most basic circumstance, nor is running water.

-Initial startup costs should include money for training, transport of equipment and materials, and administrative costs.

-Long term budget must include funds for marketing development and publicity.

-Operational and labor costs for the period of factory establishment (up to 2 years)


Q: How much does one system including the plastic bucket cost?

A: Filters produced in the field for home-use are priced from $25 USD  as there are various models and levels of subsidy. The filters are sold at a profit, this makes each factory a self-sustainable business.