Hydrologists typically assess scarcity by looking at the population-water equation. An area is experiencing water stress when annual water supplies drop below 1 700 m3per person. When annual water supplies drop below 1 000 m3 per person, the population faces water scarcity, and below 500 cubic metres "absolute scarcity".
Based on studies, the annual renewable freshwater resources in Barbados have been estimated just around the turn of the century at 225 410 m3 or 49.59 mgd per day, based on 1997 figures. Using these figures it can be seen that Barbados is a water scarce country, and it shows the need for serious policies including an immigration policy.
Using these figures Barbados would have about 82 274 650 m3 annually. If this figure is divided by a population size of 260 000, then it is clear that each person would have annual water supplies of about 316.44 m3. Therefore Barbados might be suffering absolute scarcity, if annual renewable freshwater supplies have not improved, since the turn of the century.
According to EarthTrends, an online collection of information regarding the environmental, social, and economic trends that shape our world, a major initiative of the World Resources Institute, Barbados' annual renewable freshwater resources have been estimated at 295.2 m3 per person per year for the year 2007, which is in keeping with absolute scarcity.
Barbados experienced a severe water shortage in 1994 and 1995 when the "One in 50 Year" drought caused more than 3,000 households to be without water for significant time periods.
The Government of Barbados recognized the need for Water demand management as demonstrated by the implementation of measures such as universal metering and water pricing.
Pricing policies were used to reduce, and control residential water consumption in Barbados. Results indicate that water production decreased by 12% from 1997 to 2000, coinciding with the implementation of the Universal Metering Program.
The island is characterized by a wet and dry season. The wet season, which lasts from around June to October, is the fundamental source of potable water on the island.
Almost all of the island's potable water is pumped from 21 groundwater wells in the karstic coralline area of the island, and small quantities obtained from two springs in the Scotland District.
Water is treated with chlorine to meet World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA) guidelines and standards, prior to distribution.