Absolute Minimum Requirements.
Water is required for the maintenance of
life; researchers have investigated the absolute
minimum amount of water required for human
survival. Regular intake of water is needed to
maintain a person's water balance, as water lost
through normal activities must
War and international conflicts can
worsen water-supply situations in
countries already faced with water
scarcity. Human survival can be
threatened not only by weapons, disease,
and starvation, but also by the lack of
water. Here a relief worker distributes
bottled water to refugees during the
Persian Gulf War.
The minimum water requirement for
replacement purposes, for an "average" person,
has been estimated to be approximately 3 liters
(3.2 quarts) per day, given average temperate
climate conditions.
In addition to drinking requirements, water
is traditionally used for sanitation purposes
for the disposal of human waste. Effective waste
disposal has many health benefits as it serves
to control the spread of disease. Humans also
have basic hygiene needs for personal washing
and bathing, and for food preparation. These
hygiene-related uses of water also have many
health benefits.
Drinking, sanitation, and hygiene needs
constitute the basic human survival needs for
water. These minimum needs total about 50 liters
(13.2 gallons) per person per day. In
comparison, the average American uses well over
ten times that amount. Fifty liters per person
per day maintains a person's water balance and
provides benefits vital for human health. In
2000, it was reported that 55 countries, with a
combined population of over 1 billion, average
below this basic level.