The Big Necessity: The Unmentionable World of Human Waste and Why It Matters: Summary & Key Insights

Sanitation is as old as civilization itself. When I visited archaeological sites and spoke with historians, I learned how ancient societies solved what we now call the sanitation problem long before modern plumbing existed. The Indus Valley civilization, for example, had remarkably advanced waste systems: brick-built drains ran beneath streets, and houses had private bathing areas connected to covered sewers. The Romans, so famed for their aqueducts, were just as sophisticated in taking waste away. Their public latrines weren’t merely for practical use — they were social spaces, where ideas and gossip flowed as freely as the water beneath.

But the progress wasn’t linear. With the collapse of Rome came centuries of decline. Medieval Europe reverted to primitive waste habits, dumping refuse into city streets and rivers. Epidemics followed — not just the Black Death, but countless lesser plagues that thrived on filth. Meanwhile, other cultures pursued different paths. In Edo-period Japan, waste wasn’t waste at all — it was valuable fertilizer, collected and sold. The difference between these histories isn’t just technological, it’s cultural: how societies perceive human waste determines how they manage it.

In industrial London, the problem reached crisis when the River Thames became a giant cesspool. The “Great Stink” of 1858 forced Parliament to act, commissioning Joseph Bazalgette’s monumental sewer network — a feat of engineering that not only removed waste but transformed public health. Yet that lesson, that sanitation saves lives, didn’t spread everywhere equally. Wealthy nations invested in sewers, while colonies and poorer regions were left behind. The modern world inherited this uneven legacy: flushing toilets in one place, disease and indignity in another.

When we speak of progress, we often draw the line between rich and poor nations in terms of GDP, education, or access to technology. But one of the most telling divides is the toilet divide. In places like Japan, toilets talk, sing, and even heat seats; in other regions, 2.6 billion people still defecate in fields, streets, or slums. This divide isn’t just about infrastructure — it’s about values and visibility.

I met officials who told me sanitation doesn’t win elections; voters don’t cheer for sewers. Yet the consequences of neglect are staggering. In urban slums from Nairobi to Dhaka, people pay per use for filthy communal toilets or risk violence going outdoors. In rural areas, women wait until nightfall to relieve themselves, risking assault in the dark. Meanwhile, affluent societies flush and forget, consuming vast amounts of clean water in the process.

The divide persists because waste management exists in a policy blind spot. It’s too mundane for most aid agencies and too expensive for governments focused on immediate returns. But toilets are the foundation of development. Without sanitation, clean water projects are undone, schooling attendance drops — especially for girls — and hospitals fill with preventable illnesses. Whenever I saw these realities firsthand, I was reminded of the absurd imbalance of our priorities: we can mobilize billions to fight terrorism or build the next smartphone, yet struggle to provide every person a simple latrine.