Rainwater has historically been used to irrigate crops and supply drinking water. Typically, it is harvested on rooftops and stored later. Many island nations use rainwater as a substantial part of their water supply. Even the roofs of skyscrapers in Hong Kong are used to collect rainwater.
Recently, companies began bottling rainwater falling in remote, unpolluted parts of the world. Several of these waters come from Tasmania and Chile, where air pollution is exceptionally low. Rainwater must be harvested carefully — to prevent contamination, the water must be stored quickly after it hits the collection surface. Bottled rainwater is young water with super-low mineral content. In most cases, it is nitrate-free.