Water is one of the simplest molecules: two humble hydrogen atoms (the most common in the universe) bonded to one workaday oxygen atom (itself the third-most abundant of the elements).
For such a modest molecule, it’s indispensable. We can go just days without drinking some, though we can go without food for weeks. It’s essential to our electricity, fabrics, plastics, and fuels. And that coffee you had this morning? It took nearly 40 gallons of water to bring you one cup. In fact, the American lifestyle uses more than 2,000 gallons of water a day per person.