Water

Water, a basic necessity of life is commonly known by its chemical formula H20.A public water soure is any source that serves over a minumum of 25 people or offer 15 water source connections at least 60 days a year. The purity standards have been set for public water sources by the Environmental Protection Agency (EPA). Mineral levels and microorganism levels have been set by the EPA to ensure the public safety.

http://www.epa.gov/safewater/faq/faq.html