Mapping Tools for water and sanitation infrastructure.

We are trying to map our existing water and sanitation (WASH) infrastructure facilities. I am not a GIS expert but we are constantly suggested that we should use GIS and other tools for mapping this data. I am not sure how to do that. Is there any online simple user-friendly web-based tool which can enable geographical representation of data? This mapping will help us formulate our priorities for the WASH project. Have you ever worked with these tools? What is your feedback?