The majority of living organisms are composed of at least 60% water, and human beings are almost 70% water. Our very existence is dependant upon water. Because of the intimate relationship between water and life, water is woven into the fabric of all cultures, religions and societies in many ways.
Therefore, the benefits of conserving and preserving the purity of water are enormous. To ignore this, the implications will be disastrous for human beings and the environment.
Almost all living creatures cannot survive without continual access to some form of clean, fresh water. This supply is generally considered a renewable resource, made available via the flow through the hydrological cycle. The total amount of water on Earth is relatively constant, and levels have not changed much in over three billion years. Ice ages come and go, and its availability as a liquid has changed. More recently, a surge in human population numbers and levels of consumption have increased demand, and placed enormous strains on its availability and purity.
Human life – as with all animal and plant life on the planet – is dependent upon water. We require water to grow food, generate power and run our industries. Our bodies need to take in water every day to continue functioning. We need to drink or ingest through our food about 5 litres of water per person per day, for our daily survival. We cannot survive without water for more than a few days. Without it we become dehydrated, and eventually die.
We require water to maintain a basic standard of personal and domestic hygiene, sufficient to maintain health. It is not sufficient merely to have access to water in adequate quantities – the water must be of adequate quality to maintain health, and it has to be free of harmful biological and chemical contamination.
Freshwater withdrawal in the US increased steadily until approximately 1980. Up until 1980, supply matched increasing population. Since 1980, freshwater withdrawal has remained constant, yet the population continues to rise. Currently the United States utilises approximately 450 billion gallons of water on a daily basis.
In a typically developed country, water for domestic needs represents a relatively small amount of the total quantities withdrawn for other uses. By far the largest consumer of fresh water is agribusiness for irrigation, followed closely by energy companies for thermoelectric power. Government public services use approximately 15%.
Typical water usage in the USA - Freshwater withdrawals (surface-water and groundwater)