Basic and Advanced Water Harvesting System Basics
Based on an article from energy.gov
The most basic rainwater harvesting system includes a way to collect the rain (often the roof of a house), a way to guide the rainwater (like a gutter and downspout), and a place to store the water (something as simple as a barrel). Due to the lack of filtration and proper storage, water collected from a simple system like this would only be appropriate for watering a garden, fire suppression, or as grey water (like toilet water).
An advanced system would provide more uses for the water and would include a collection system with several layers of filters to keep dirt and debris out of the resulting water. An appropriate storage tank would need a way to safely handle water overflow and be made from materials that won’t leach into the water while inhibiting bacterial growth. The container can also be then hooked up to a control system that will further filter the water to drinking-level purity if needed. Lastly, the advanced system would require a pump to direct water, a flow meter, and a backflow prevention system, all of which would need to be hooked up to a power source.