The use of appropriate equipment paired together with adequate training helps communities in the developing world to meet their own demand for water at a cost they can afford. Extremely light and portable equipment can be used to drill. Sound application of drilling equipment requires common sense to achieve good results. To open a hole all actions must adhere to some basic operational rules defined by existing field experience, together with accepted engineering theories, if the drilling and well construction are to succeed. This manual explains in practical terms the basic drilling techniques. It describes the use of fluid circulation in soft ground formations, and compressed air and hammers for hard rock. It discusses well design, types of pump and their installation, screen selection and testing.