In order to supply and procure the drinking water of South and South east of Tehran, the project employer, Tehran Water and West Water Company, gave priority to the construction of the filtration plant with the final capacity of 5000 liters per second, and the construction of the project building began in a land measuring 15 hectares.In the present project, the Arched Modular Formworks System was applied for the arched walls of the reservoirs. In the height, for the purpose of safe concrete pouring, the lift system was proposed and such a suggestion caused thriftiness in the number of formworks and also increased the speed in execution of such a project.