Kamal Ghorui
Bermuda is an island in the middle of the North Atlantic Ocean, and it has no rivers, no lakes, and no natural springs of fresh water. For more than 400 years, the islanders have been relying on a brilliant but simple idea: Every roof is a collector of drinking water. The island’s famous white, stepped roofs are not just a picturesque postcard image; they are a rainwater-harvesting system that has quietly and successfully served the islanders through storms, droughts, and centuries of change. Modern research in the Journal of the American Water Resources Association (JAWRA) still points to Bermuda as a living example of how traditional design. The system is resilient and sustainable
Bermuda’s rainwater‑harvesting roofs
Geologically, Bermuda is a porous limestone platform in the ocean. Consequently, there is very limited usable groundwater. In fact, what are referred to as lakes and wells are brackish and salty. The first settlers quickly realised they could not rely on rivers and wells for water. They decided to use rain. Their solution to collecting rainwater is the Bermuda roof. It is a stepped limestone roof that is whitewashed. It slows down rainwater and directs it to gutters and storage tanks. Roof-top rainwater harvesting is “mandated by law” for all domestic buildings, according to a 2011 study at JAWRA. It is the primary source of water for many homes. In fact, according to a government-endorsed article published in 2017, “the vernacular buildings and rainwater harvesting solution are now regarded as a cornerstone of the island’s integral water management infrastructure.
How the 400‑year‑old system still works
As Bermuda Geology puts it, “Each Bermuda home is, in effect, a mini-water treatment plant. Rain falls on the stepped roof, which is designed to keep water droplets moving slowly so they can be picked up cleanly. The water is then channelled into underground tanks, which can be large enough to store several months’ worth of water.”In the past, the roofs were covered in lime wash, which had antibacterial properties to keep water clean. Today, we retain the white paint for other reasons. It reflects ultraviolet light, which further purifies the water and inhibits algae growth. “An engineering overview says that the average Bermudian home can collect hundreds of thousands of litres annually from its roof catchment system. It is a staggering feat, even by modern standards.“
Lessons for a world facing water scarcity
The Bermuda story is not one of a clever roof design, but one of planning for a harsh reality. The 2011 academic paper on rainwater harvesting in Bermuda reads, “This rainwater harvesting system provides an opportunity to maintain a system of water supply based largely on traditional self-sufficiency and sustainability.” This is clearly a different model from the sprawling and energy-intensive systems that must be maintained to provide water over great distances. The island model has been noted as a case study for other regions threatened by drought and saltwater intrusion due to climate change. In a conversation with Water Advocacy, Dr Edward Harris, Bermudian archaeologist and water historian on the rib roof rainwater harvesting model says it “provides a logical insight into the Bermuda system of collection of drinking water used for over 400 years.”
Modern Bermuda and the future of the white roofs
Although the island still cherishes its roofs, it has supplemented these with new technology. New desalination plants have been installed to provide the additional water required, particularly due to the rise of tourism and the need for water in industrial processes. However, the roof-tank system still remains the main source of water supply. A feature published by the Engineering Institute of Technology in 2017, sponsored by the government, indicates that more than half of the dwelling units have no well or connection to the mains water supply and rely almost exclusively on the collected rainwater.Today, the white roofs have become a symbol of independence and identity for the people of Bermuda. As a recent article writes, “The island sees this as a defeat, and the roof is tied to a tradition of independence.” The answer for water-scarce cities worldwide is quite simple: just as the islanders did 400 years ago, when you have no rivers or lakes, the sky is your river, and your home is your water security centre.
