No rehydration for a day is a trying experience, for two days it becomes perilous, for three days it is usually fatal. Beyond this existential necessity, translating to a per capita average of about 750 kilograms (or liters, or 0.75 cubic meters) of water a year, there are several other—and much more voluminous—water needs: for personal hygiene, cooking, and laundry (even without an indoor toilet, these categories add up to the minima of 15–20 liters a day, or about 7 cubic meters a year), for productive activities, and, above all, for growing food.[17]
