Here in Canada where water, particularly in its 'snow' form, seems to be in overabundance right now, it's worth noting this rather sobering opening paragraph (that's me bolding some parts for emphasis) in that review article: The many problems worldwide associated with the lack of clean, fresh water are well known: 1.2 billion people lack access to safe drinking water, 2.6 billion have little or no sanitation, millions of people die annually—3,900 children a day—from diseases transmitted through unsafe water or human excreta1.... In both developing and industrialized nations, a growing number of contaminants are entering water supplies from human activity: from traditional compounds such as heavy metals and distillates to emerging micropollutants such as endocrine disrupters and nitrosoamines.