Traditionally rain water has been one of the few water sources known to usually be clean and safe to drink. Today water harvesters must be wary of pesticide contamination, high mineral levels, bacteria and other impurities in their runoff water. Filtering technologies have been used in the past and today to purify it by passing it through a series of rocks, gravels, and sands to scrub out contaminants. These methods have proven to be very effective.
Sustaining Animals: Because of animals’ higher tolerance for bacteria and other impurities, harvested rainwater is often used as the primary source of water for livestock. Since cattle and sheep are well adapted to drinking rainwater, safer groundwater is often saved for human drinking.
Groundwater Recharge: This is one of the more modern applications for water harvesting. Rain runoff from buildings, parking lots and other man-made structures is funneled into seepage ponds or deep wells in order to directly recharge aquifers.