The objective of this work was to present the design of a system for rainwater harvesting in the climatic conditions of the city of Belém, PA, as an alternative for rainwater use in poultry production. In the experiment equations provided by EMBRAPA and NBR 10.844 (1989) were used for the calculation. The study focused on a poultry house with a capacity to raise 12 thousand birds. Through the survey of rainfall indices of the region of Belém - PA, in the period from 1996 to 2015, it was found that the average annual rainfall was 3264.27 mm/year. Being a monthly average of 272.02 mm/month. From the rainfall data, it was found that the roof area for the necessary collection would be 1000 m² and that the amount of water that would be collected was sufficient to maintain the demand of the 12,000 birds housed in the aviary during the period of greatest demand for water and even sufficient to generate surplus through the installation of a 60 m3 cistern.
