Assessment of Rainwater Harvesting Potential for Domestic Use in Zamfara State

Zamfara State in North West Nigeria experiences distinct wet and dry seasons, and the potential for rainwater harvesting to supplement domestic water supply during dry periods offers a technically feasible and community-appropriate solution to water access challenges. This study assesses the rainwater harvesting potential for domestic use in three Local Government Areas of Zamfara State: Gusau, Kaura Namoda, and Anka. Mean annual rainfall data from the Nigerian Meteorological Agency (2010 to 2022) were analysed, and roof catchment areas and storage requirements were calculated for representative household typologies. First-flush volumes required to achieve acceptable water quality are estimated from available quality monitoring data. Community surveys of 150 households provided data on current water access, existing rainwater use practices, and willingness to adopt formal rainwater harvesting systems. Results indicate that the mean annual harvestable volume from a 60 m2 roof surface ranges from 24,000 to 36,000 litres, sufficient to supply domestic non-potable needs for a six-person household for approximately 180 dry-season days when combined with a 10,000-litre storage tank. Currently, only 22 percent of surveyed households practise any form of rainwater collection. Material cost for a complete basic system is estimated at 85,000 to 120,000 naira. The study recommends a state-subsidised rainwater harvesting programme targeting school compounds and community health facilities as priority installation sites in Zamfara State.

Keywords: rainwater harvesting, domestic water supply, dry season, Zamfara State, North West Nigeria