THE CARIBBEAN

Rooftop catchments and cisterns have met the water needs of many small Caribbean islands for over three centuries. More than 500,000 people depend on such systems of water storage. In Saint Lucia, storage systems include 200-litre steel drums, large polyethylene plastic tanks with a capacity of 1,300*2,300 litres, and underground concrete cisterns that hold anywhere between 100,000 litres and 150,000 litres.

The Turks and Caicos Islands have many government-built rainfall catchment systems. Here, government regulations make it mandatory for all developers to construct a water cistern large enough to store 400 litres per metre square of roof area.

Rooftop and artificially- constructed water storage systems are common in the Bahamas. Whale Cay even has a piped distribution system for water captured from rooftops. Industries also use rooftop rainwater, and piped water supplies are supplemented by rainwater from rooftop catchment cisterns in multi-storeyed apartments. In the Isles de la Bahia off the shores of Honduras, rainwater caught on rooftops meets a substantial portion of the drinking water needs.

A rural water supply study for Jamaica concluded more than 100,000 Jamaicans, especially those lacking access to rivers, springs and wells, depend significantly on rainwater catchments.

In some of these island states, governments regulate the design of rainwater harvesting systems. In USA's Virgin Islands, the law requires all new buildings to make provision for rainwater harvesting.