The water crisis is a problem for almost all countries in the world. Rainwater has the potential to be developed as a water supply due to the large amount of polluted surface water. Bio-slow sand filtration (SSF) has long been proven to be able to improve the physical and biological quality of water. Modification of SSF in this study is bio-activated carbon from Moringa oleifera seeds, coconut shells, and lava rock as filter media. This study aims to examine the effectiveness of bio-SSF to treat rainwater as a water supply. Bio SSF uses transparent polypropylene with a diameter of 0.2 m and a total height of 1.5 m. The composition of the media used consisted of lava rock measuring 4.75–12.0 mm (10 cm), coconut shell charcoal measuring 1.18–4.75 mm (10 cm) and Moringa oleifera charcoal measuring 0.150–1.18 mm (80 cm). Samples were flown intermittently at a rate of 20 cm/hour at 20-25 C. Parameters observed were pH, E. coli, TDS, Fe, Pb2+, Cd2+, and ammonium. All parameters tested met the requirements for clean water as regulated by the Minister of Health of the Republic of Indonesia No. 32 of 2017.