Abstract: A filtration system for filtering out bacteria, Giardia cysts, turbidity and other impurities in raw water supplied to a home or the like including a sealed container divided into an upper and a lower chamber by a support plate, the support plate supporting a quantity of filter material sufficient for filtering out undesired bacteria, turbidity and other impurities from the raw water; the sealed container having a raw water inlet pipe communicating with an inlet area above the filter material for supplying the raw water, and a filtered water outlet pipe communicating with the lower chamber for exhausting filtered water from the container; and further including a geofilter cloth provided on top of the filter material for supporting a biological "schmutzdecke" growth thereon which, along with the filter material, filters out bacteria, turbidity, Giardia cysts and other impurities.