In the present article, the results of the work entitled "Design of a Prefeasibility Cost Model for the Construction of a Veredal Sewer in Cundinamarca, Developed by a Medium Enterprise" are presented. Medium-sized companies, analyze and facilitate the decision-making in the economic convenience to present economic technical offers for the construction of this type of works a department level of Cundinamarca, given that these correspond to Rural sanitation works framed within programs carried out by The Aqueduct Company,. Sewerage and Cleaning of Bogotá S.A. E.S.P., EAB S.A. ESP, attached to the Habitat Secretariat. For the above, the theoretical basis of the ABC cost system is considered as a tool for cost analysis and monitoring of activities in combination with management processes in the PMBOK 5 edition, in cost management; Methodologies that try to guide business management so that it efficiently and get better performance and arrive at a result with greater satisfaction, in addition to making high-level decision making.