Supported Factor (E) Ventures to estimate the current and potential market size of small solar based water pumps and their channels of distributions in Kenya, Uganda and Tanzania through a rapid scoping study. GIS based analysis was complemented by primary data within Kenya covering current water pump users within 100-kilometer radius of Nairobi which included Kajiado, Machakos, Matuu, Sagana, Kijabe, Naivasha and Narok areas.