Environmental concerns and values are not static; they change depending on the zeitgeist of the time. Currently, the focus on clean drinking water reflects the societal preoccupation with health and wellness.
Steven Cohen of The Huffington Post explores the connection:
Bowman identified other surveys indicating that the public was increasingly concerned about the quality of the tap water they were drawing from public water systems. I believe that concern over tap water is part of the growing movement for locally-sourced food, physical fitness, and what has been termed “wellness.” The underlying source of support for environmental protection is a growing understanding of the relationship between a toxic environment and human health.
People wearing face masks in Asia to filter out air pollution, the popularity of bottled water, growing concern about the impact of football and boxing on the human brain, fast food salad meals, bans on public smoking, increases in auto safety equipment—all of these trends are part of a growing knowledge of health risks, and people are willing to take action to reduce those risks. For many people, a clean and healthy environment is deeply related to an effort to manage health risks, and they will therefore support government action to reduce pollution.