Over the past few decades, there has been an increase in global population. This increase has resulted into greater consumption of resources such as water, thus putting a strain on the water resources available for use on earth (Charania, Principles of Hydrology for Practising Engineers: Basic Hydrology, 2016).

Based on the latest United Nations estimates, as per October 21st 2018, the population of Kenya stands at 51.3 million. This shows an annual growth of around 2.5% every year. The approximate population of Nairobi is around 6.5 million in the metropolitan area and 3.5 million in the city proper as per 2009.The Ongata Rongai population has increased from 40178 in 2009 to approximately 66042 in 2018.The increasing population is due to the rapid urbanization.

Access to quality safe water is an indicator of improved social- economic development for any community. Due increasing population, change in land use, Chepalungu sub-county has been under pressure to fulfill access to quality safe water. Despite the government plans to ensure that all households have access to clean water, but this has not been the case in chepalungu sub-countyas the coverage remains low. Due to this situation the residents of Chepalungu resorted to constructing water pans to conserve runoff water during raining season.