This chapter discusses the rudiments of a Computer Aided Design and Drafting (CADD) system. It reviews the hardware and software requirements of a CADD system for water and wastewater applications. The chapter also discusses the concepts of computer aided mapping and retrieval of such information for management and other design applications. Computer aided design and drafting systems provide automated mapping, design and drafting and interactive information. The interface between the graphic and non-graphic data is very essential for water and wastewater applications. Mapping is the digital graphic representation of the facilities and digital interface of the facility attributes with the graphic data. Among various CADD system vendors, two vendors in particular are known for mapping. These are Intergraph and Synercom. Other CADD systems include Applicon. CADD procedures via menu use the mapping practices to create drawing files. The manual system is maintained with drafting standards or mapping practices.