Water & Life

How we came up with those numbers of gallons

We need water every day to live. If we don’t drink plain water, we need to take in other liquids or foods that contain water.

On the Hub Resource Forms, we offered the option “share” and said that it means “if we have more than 5 gallons per day per person who lives at this Hub, or more than 30 if we also grow all our own food, then we will share the excess water with other people who are on our Island to save a life.” Here is part of what we were thinking about when we came up with those numbers.

One gallon: To keep our kidneys flushing toxins out of our bodies, we adults must produce at least a cup of urine every 8 hours (3 cups a day.) We sometimes produce much more than that, even if we are dehydrated, particularly if our blood sugar is over 200. We also lose fluids from our intestines, skin, and lungs. The amount depends on many things including our temperature, how dry the air is, what we are doing, and whether we have certain illnesses. We may be able to survive drinking 4 cups of water a day, but many of us do better with up to a gallon.

Two gallons of water a day per person can keep many of us alive, somewhat clean (wiping our whole skin with a wet washcloth daily and washing hands often), and eating with plates and utensils that have been cleaned with care.

Five gallons per person per day can allow for the above plus some drip irrigation of a few plants, occasional hand-washing of key pieces of laundry, and the keeping of a backup supply of water in case of dehydrating illnesses.

Thirty gallons per person per day (in addition to the rain that falls directly on the food garden in a “normal” year) is enough to grow all the food one person needs using bio-intensive gardening techniques—which takes about 25 gallons—plus 5 for flushing our kidneys, sparingly cleaning our dishes, taking washcloth baths, frequent washing of hands, occasional washing of key pieces of laundry, and the keeping of a backup supply of water in case of dehydrating illnesses.

Numbers of gallons used per person are much higher if we also use drinking water to flush toilets, fill hot tubs, wash pets or cars, use standard (industrial) methods of growing food, or keep clothes immaculate. Millions of people have lived long, full lives without using drinking water in these ways.