The library
Short explanations first. More depth if you want it.
Most tap water starts as rain or snowmelt. It runs over land, sinks into aquifers, or collects in reservoirs before a utility treats it and pipes it to you. Every step adds a chapter to its story.
Natural water dissolves small amounts of rock as it travels — calcium, magnesium and others. That's why spring waters taste different from one another, and why some filters add minerals back.
Rain falls through air. It soaks into soil. Plants drink it, animals eat the plants, and we eat both. What enters one part of that loop can travel to the others.
In roughly two centuries, people learned to make materials and compounds at a scale nature never had. Many improved life enormously. Some also changed the chemistry of the air, water and soil around us.
