Water scarcity refers to the shortage of available water resources to satisfy water needs in a region. This problem affects all the continents on the planet and about 2.8 billion individuals all over the world suffer from it at least during one month in a year. The number of people that does not have access to clean drinking water is more than 1.2 billion. Water scarcity is a three-fold concept involving water stress, water shortage/deficits, and water crisis. Water stress is a rather new concept and it refers to the difficulty in securing fresh water sources for use during a time period. Water stress may lead to further exhaustion and deterioration of the available resources of water. Water shortage is generally caused by climate change like changed weather-patterns (like droughts or floods), more pollution, and increased demand and usage of water by humans. Water crisis is a condition in which there is less available unpolluted potable water than the demand in a region.