The challenge
Across rural Siem Reap, families drink from sources contaminated with the bacteria and parasites that cause chronic diarrheal disease. The fix is one of the most studied, most reliable household treatments in the world — it just needs funding.
A biosand filter is a concrete box layered with sand and gravel, topped by a living biological layer that removes pathogens. No moving parts. No consumables. Decades of clean water.
Our solution
Our partner, the Trailblazer Foundation (working in Cambodia since 2004), already runs an excellent program. For about $100 they build and install a concrete household biosand filter that serves 15 people up to 80 liters of clean water a day, for decades — no power, no consumables, no moving parts.
Families pay a token ~$3.65 into a village savings fund rather than receiving a pure handout — a small buy-in that builds the ownership that makes systems last. We’ve funded five filters so far and verified the results. This is our purest funding play: 100% of donations become filters, never overhead.
Who does what
We are force multipliers, not occupiers — the local partner leads and we supply the science, the design, and the funding.
- Fund filters and wells
- Spot-check treated-water quality
- Publish exactly what each donation built
- Build and install filters household by household (Trailblazer)
- Dig and finish wells
- Train families on use and care
The team behind it
Volunteer scientists and engineers donating their expertise to this project — click anyone to see their work.
From the field
