The Calabash Tank Manual

The Calabash Tank Manual is published by the Dutch organization Clean Water Healthy Village (degevuldewaterkruik).Paul Akkerman, who wrote the manual, co-founded this rainwater harvesting project in Bedanda, Guinea-Bisseau, in 2005. Working with Bicosse Nandafa, he sought to provide an alternative drinking water source as aquifers in the country’s coastal region experienced pronounced saltwater intrusion during the dry season. Through this intervention, Paul and his colleagues were able to provide an alternative drinking water resource, during a socio-environmental crisis in which children were becoming ill and dying of diarrhoea. A long-standing commitment to SDG 6 (ensure availability and sustainable management of water and sanitation for all) has led the project to assist two thousand families in building rainwater tanks in Guinean-Bissau’s coastal region. 'Clean Water Healthy Village’ has also organised training programmes for masons and project managers in DR Congo, Nigeria, Tanzania, Senegal and Guinea-Conakry. On completion of the programme, masons receive certification, enabling them to build Calabash Tanks in their own communities. IRHA salutes Paul Akkerman’s work. He truly is a rainwater-harvesting hero.

WHO guidelines for Drinking Water Quality state that rainwater-harvesting systems offer drinking water with low health risks, if they are located within clean catchments, use covered storage tanks, and employ appropriate point-of-use treatment (2017 Guidelines, 4th ed.).

The construction techniques used to build the Calabash Tank, as detailed in Akkerman’s recently published manual, were refined over a decade, drawing on the skills and methods of local artisans. The resulting reservoir is a simple, sturdy structure that is easier to build than earlier versions of the tank. In Guinea-Bissau, the cost of building one of these 5000 litre tanks is 240 euros. In contrast, it costs between 500 and 1000 euros to buy a 5000 litre PVC tank. The manual details numerous other advantages of cement tanks: for instance, water in cement tanks remains cooler than in plastic tanks. Additionally, cement tanks last for more than 25 years, as compared to 5-10 years for PVC tanks.

To download a Calabash Tank manual in English, French or Portuguese, please refer to the degevuldewaterkruik website.