The water you use to brew your tea makes an enormous difference to its flavor. It is commonly believed in China that each leaf is best infused with water from its place of origin—hardly practical in America, obviously. If you're going to invest in fine teas, though, don't ruin them with chlorine-laced tap water or even bottled water with an unsuitable mineral content. If you have access to a spring, an unpolluted stream, or a well, artesian or otherwise, by all means try its water. If you use bottled water, remember that waters with a high mineral content (Evian, for instance) seem to bring out the richness and sweetness of green tea, while those with a low mineral content (e.g., Volvic) make the finest infusions of other types of tea.