International statistics confirm the ongoing failure of many poor (and often tropical) countries to ensure all their citizens have access to affordable domestic water of adequate quality and quantity. The constraints on improving the situation are economic, organisational, climatic and topological. In several countries some of these constraints are worsening and in many countries resource and social sustainability are not assured. Although practised in antiquity, roofwater harvesting has resurfaced in recent decades as a ‘new’ technical option for water supply.
It has advantages and disadvantages whose strengths depend heavily upon such loca factors as settlement structure, geology, community wealth, house design, seasonality and reliability of rains, government policy and water laws, and the perceptions of potential users. The paper reviews these advantages and disadvantages in the specific context of low-income tropical countries, giving special emphasis to their more humid regions.
Recent research findings concerning both the technique of roofwater harvesting and its application are reviewed.