Empirical evidence on the potential of rainwater harvesting for residential water supply in Accra

We evaluate the potential of rainwater harvesting for residential water supply by estimating, analysing and comparing the per capita water consumption accessible from rainwater harvesting (RWH) systems and that acquired from water tanker services (WTS) for single-family households in Accra, Ghana. Although the values from WTS stochastically dominates those from RWH over a wide range, the difference in their mean values does not appear to be statistically significant, and the probabilities that the per capita water consumption, of a household selected at random, exceeds the WHO service levels of {5, 20, 50, 100} lpcd are {1.000, .937, .239, .0474} for RWH, compared to {1.000, .994, .555, .0467} for WTS. We conclude that for single-family dwellings in Accra, the WHO service levels for water consumption and hygiene obtainable from RWH is appreciable and comparable to those from WTS providers. Therefore, households can satisfy their current water consumption levels with RWH alone.