Pee isn't (just) from what you drink. There's not a 1-to-1. Eating and drinking goes through digestion. Food and liquids are absorbed in your small intestine, enter your blood stream, and are processed by the liver. Glucose and nutrients are transported to cells by your red blood cells. They also carry oxygen from your lungs.

Waste of various kinds, byproducts of cells using energy, enters your bloodstream and is carried by red blood cells to your lungs (carbon dioxide) for air-soluble waste and kidneys (urea, salts, etc) for water-soluble waste. Kidneys help keep the balance of water and salt just right. Water soluble waste happens to be yellow. It comes from cells metabolism, breathing, bile, excess soluble vitamins and nitrogen wastes (from protein) and it is dissolved in water.

The rest of what you eat and drink is digested, or is indigestible, and leaves as solid waste. Bile and dead red blood cells and fiber and other non-soluble waste becomes poop.