English Abstract: As established by the World Health Organization WHO, the most effective way to systematically ensure the safety of a drinking water supply system is to apply a comprehensive approach to risk assessment and risk management covering all stages of the supply system, from catchment basin to distribution to the consumer. The main objectives of a Water Safety Plan (PSA) are: minimizing contamination of water sources, reducing or eliminating pollution through appropriate treatment processes, and preventing pollution during processing, distribution and storage. In this sense, the design of the Water Safety Plan (WSP) for the water supply system of the town of Tocaima, located in the department of Cundinamarca, is presented. The WSP for the company INGEAGUA S.A.S. E.S.P., is assessed on the basis of specific criteria based on the World Health Organization's Manual for the Development of Water Safety Plans; after that study the control measures to be taken in the presence of the risks and dangers encountered are presented and subsequently defined how they could react when implementing such measures. The analysis identified significant risks to the quality, quantity and continuity of service. First, the source of supply is affected by agricultural activity and sewage discharges. The catchment is located in an area with easy access to tourists and the grid does not fulfill its function, because in the driest times, the flow is minimal and the catch is made below the minimum necessary. In terms of treatment the plant is designed to work with three mechanical flocculator palletisers but only one of them works correctly; another is out of service and the third is retired. The disinfection is not carried out correctly because the chlorine enters directly into the tank without undergoing a mixing process that guarantees that the percentage of residual chlorine is the indicated one. The methodology used is the one proposed by the World Health Organization (WHO), which provides a series of parameters to follow when developing and executing a water safety plan (PSA). It is composed of 5 phases of preparation, evaluation of the system, operational monitoring, management and communication, feedback and improvement of the system, which in turn, are divided into 11 modules. There is still little application of the methodology in the country
