Three Sources, One Island
Bermuda is a 21-square-mile island sitting alone in the North Atlantic — with no rivers, streams, or natural surface freshwater of any kind. Every drop the island uses comes from one of three sources, and understanding them explains why Bermudians pay such close attention to the weather.
Roof catchment ("the tank") is the oldest and most culturally ingrained. By law, every building must harvest rainwater from its white-painted limestone roof into an underground cistern — what Bermudians call the tank. When it rains, your tank fills. When it doesn't, you start watching the sky. Bermudians take their water personally — I once watched a colleague in Hamilton refuse a glass because he thought it was reverse osmosis. Our department head insisted it was fresh rain water. My colleague paused, then asked, "Well, is it town rain water?" — as if rain collected in Hamilton couldn't possibly match water from Somerset or St. Georges.
Reverse osmosis desalination supplements the supply — six plants around the island produce roughly 13,500 cubic metres per day, about a quarter of total consumption.
A freshwater lens sits underground, where fresh groundwater floats on heavier saltwater inside Bermuda's porous limestone. Over 3,000 households tap into it via private wells, though the water is slightly brackish and used mainly for non-potable purposes like flushing and garden watering.
Even with desalination and the lens, tank rain still matters deeply. A good rain can mean the difference between a full tank and calling the water truck.