Here’s an example of a homemade bio-sand water filter that is used for filtering rainwater collected in rain barrels. See an earlier post that explains how a bio-sand water filter works. If you intend drinking water from your rainwater harvesting system, it is recommended that you filter the water either at source (e.g. at your water tank) or at point of use (i.e. at the water faucet). Contact us for all your rainwater and greywater recycling requirements. Water Rhapsody water systems save you money, save water and save the environment.