BioSand Filters (BSFs) are an inexpensive, point-of-use, household water filter that uses gravity, sand, and natural biological processes to remove pathogens from water (up to 98% of bacteria!) and can last for more than 25 years. Traditionally, steel molds have been used to cast concrete BSFs, but these molds are heavy, expensive, and require a skilled welder. OHorizons have engineered a DIY Wood Mold that is typically 10x less expensive and can be built using 100% locally available materials, so that organizations can make more filters, faster. By reducing the financial and technical barriers and by making the construction manual open-source and free to download on the website, OH hope to empower communities around the world to live healthy, productive, and dignified lives. The Wood Mold is field-tested. It has been used in pilot projects in Mali, Ecuador, & Bangladesh. This year, 5,000 people in Bangladesh will receive safe drinking water access through the provision of the BSFs.