Given its geology, Bermuda has no rivers, streams, lakes or freshwater ponds for obtaining freshwater. Thus, for basic survival, the first settlers were obliged to meet their drinking water needs by way of rainwater harvesting. Water was collected on roofs, where gutters on the roof surface diverted rain water into down spouts and subsequently into storage tanks. Until the 1930s, rainwater provided the only source of potable water. 

From the small original cottages to the office blocks of today, for 400 years roof-top rainwater harvesting has been practiced in Bermuda and continues to be the Island's primary source of drinking water. Today, roof-top rainwater harvesting is mandated by law for all buildings in Bermuda, with approximately 85% of Bermuda residents currently using their tank water for drinking on a regular basis.

Bermuda’s legislation and building codes specify that all buildings are required to have rainwater catchments and tank(s) to supply and store rainwater for people occupying or using the building. Buildings must have at least 80% of the roof area sufficiently guttered to catch rainwater and have a water storage tank with a capacity of at least 100 US gallons (378 litres) for every 10 square feet (0.9 square metres) of catchment area. 

Rainwater harvesting is particularly suitable to locations where the average rainfall exceeds 400 mm/year and other sources of water are scarce and/ or of poor quality. Bermuda has an average annual rainfall of approximately 1400 mm and precipitation is fairly evenly distributed through the year, with the exception of the slightly drier months of April and May.

Given the broad, multi-disciplinary and national scope of rainwater harvesting and water management in Bermuda, new initiatives are currently underway to develop holistic and long term-term strategic approaches to water management on the Island, so as to ensure the sustainability and resilience of this intangible cultural heritage