Water and Sanitation Corporation (hereinafter, called WASAC) and Japan International Cooperation Agency (hereinafter, called JICA) are coducting the project for strengthening operation and maintenance of Rural Water Supply Systems in Rwanda (hereinafter, called RWASOM) since 2015. RWASOM mainly supports 4 model districts - Rwamagana, Kayonza, Ngoma and Kirehe at the Eastern Province in Rwanda. The project conducts developments of manual and capacity building of WASAC, Districts and Private Operators. <br> Currently, most of countries focus SDGs to achieve 100% water access by 2030. Because of that, it is very necessary to collect and analyse the GIS inventory data for water supply management, especially planning and improvement of operation and maintenance. <br> Now WASAC has started to map all of water facilities data in rural area under support of RWASOM since July 2018. Then, we also started to use collected data by offline since Feb 2019. <br> We spent the minimum budget to conduct our mapping and data sharing without customizing FOSS4G so much. This our approaches might be very useful for other users in developing countries. So we would like to share our experience and approach of FOSS4G in Rwanda.