The homeowner planning a system for outdoor use will find most of the needed information herein. Figure 1 is a generalized schematic of a rainwater system, showing examples of each system component. In special circumstances, paved patios or decks can be used to collect rainwater. Generally though, the available catchment area is the roof Figure 1. Basic rainwater harvesting system of the home, barn and outbuildings.
Any roofing material is acceptable for collecting water for non-potable uses.
Water to be used for drinking should not be collected from roofs covered with asphalt shingles, and lead flashing should not be used in these systems. They should be suspended from hangers no more than three feet apart. Aluminum or galvanized metal are recommended because of their sturdiness, although inexpensive plastic gutters may serve beneath small roof areas. The downspout should be sized to provide at least one square inch of opening per 100 square feet of roof area. Provide a downspout for each 50 feet of gutter run.