Rainwater has historically been used to irrigate crops and supply drinking water; typically, it is harvested on rooftops and stored for later use.
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 rain. Recently, companies began bottling rainwater falling in remote, unpolluted parts of the world. Several of these waters come from Tasmania, where air pollution is extremely negligible. 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 an extra-low mineral content. In most cases, it is nitrate free, though bottlers usually filter the water.