How the BioSand Water Filter Works

Samaritan's Purse is providing clean water to families amidst a growing body of evidence that BioSand Water Filters save lives.

Samaritan's Purse is providing clean water to families around the world amidst a growing body of evidence that BioSand Water Filters save lives, restore health, enable parents to work more and their children to study more, and generally improve the quality of life for filter owners.

Today, as an estimated 1.4 million children die every year from diseases caused by drinking polluted water, the evidence in support of BioSand Water Filters from reputable, independent researchers continues to grow.

Learn more about BioSand Water Filters and how they work

School and Community Filters
Samaritan’s Purse has adapted the household-oriented BioSand Water Filter technology to create significantly larger filters that serve schools (225-300 students and staff) and/or small communities. We are building and installing the filters in southeast Asia and Latin America. You are welcome to join one of our volunteer “Water for Kids” teams trips to Cambodia to build and install filters at schools

Researchers from Laval University in Quebec recently partnered with us to study the effectiveness of these larger filters, which we call “Samaritan Filters,” and concluded they are very effective. Field tests in Cambodia showed Samaritan Filters removed 97.8 per cent of the potentially deadly E. Coli in communities’ unfiltered water. The Samaritan Filters also reduced the turbidity or cloudiness of the unfiltered water by 82 per cent—making it almost twice as clear as the World Health Organization’s turbidity guideline. You are welcome to read a summary of the research study.

BioSand Filter Research
There have been several research studies of BioSand Filters. Among them is research from The Water and Sanitation Program, a partnership administered by the World Bank to help poor people have affordable, safe, and sustainable access to clean water and sanitation.

Read the Water and Sanitation Program Field Note

Read the Executive Summary

The World Bank study focuses on households in rural Cambodia, where Samaritan's Purse and its local partners have been building and installing BioSand Filters for decades. Researchers concluded that households using BSFs experience 47 per cent less diarrheal diseases than households without BSFs.

The World Bank study also found that filtering untreated water through BSFs reduces levels of potentially fatal Escherichia (e-coli) bacteria by 95 percent and of turbidity (cloudiness) by 85 percent.

In summary, BioSand Water Filters are saving lives. And your donations are helping us build and install thousands of these filters around the world.

Other findings from the study include:

  • BSF-equipped households experienced between 4.4 to 6.3 cases of diarrhea per year compared to 8.0 to 9.9 cases per year among households not equipped with a BSFs
  • The incidence of diarrheal disease among two to four years olds in BSF-equipped households was 44 per cent lower than in non-BSF households
  • Continued usage rates are higher for BSFs than for some other "point-of-use" water treatment options
  • BSF performance is comparable to some other recommended treatment options, but BSFs have advantages: they can be built using locally available materials and have no moving parts
  • Recontamination of stored treated water remains a challenge to maintaining clean drinking water quality for all treatment options
  • Despite recontamination during storage, concentrations of e-coli and cloudiness were still lower in BSF-treated and stored water than in untreated water

The World Health Organization and UNICEF say the health improvements from a 50-per-cent reduction in the number of people without access to clean water would result in an extra 272 million school attendance days and 320 million productive work days each year in the developing world - resulting in major economic and social benefits.


Ways you can help


Please pray for those who continue to suffer without clean water. Pray that their needs may be met and that through the aid of Samaritan's Purse they will know God's deep love for them.


The need is urgent. Someone - often a child is dying every 37.5 seconds in the developing world from diseases caused by polluted water. A gift of $150 provides a life-saving BioSand Water Filter and related health and hygiene training to a family in need. Donate Here