生物沙濾水器使用石子、沙子以及自然的生態處理過程來過濾水中的污染物，成為可以引用的水。這是一個非常棒的低科技（low-tech）水處理方案：
- 完全不需要電力
- 使用 100% 在地可取得的資材（不像有些大型社區形系統需要仰賴外地進口主要零件）
- 勞力密集而非資金密集
- 非常耐用，若是維護得當，可以用 25 年以上
- 只需要非常少的維護
- 非常有效的可以去除細菌、病原菌、蠕蟲，並且降低混濁程度
這個影片裡面則使用 PVC 水管來製作濾水器，非常簡單實用：
History of the Biosand Filter
Dr. David Manz developed the household biosand filter in the 1990s at the University of Calgary, Canada. In 2001, CAWST was founded to provide the professional services needed for the humanitarian distribution of the filter in developing countries. As new research becomes available, CAWST periodically updates the biosand filter design and recommended operating conditions to provide better water treatment. The current recommended filter is Version 10.
As of 2013,CAWST estimates that well over 650,000 biosand filters have been implemented in 55+ countries around the world, benfitting more than four million people.