Desalination is increasingly becoming an integral part of water management strategies of several countries worldwide. However, it causes environmental impacts that need to be further assessed. This includes the disposure of end-of-life reverse osmosis (RO) elements. Hence, this work proposes a methodology to estimate and forecast the disposure of these elements without fixing the membrane lifespan. To this, a time-step model was applied for the first and the ARIMA model was used for the latter. It was possible to estimate a generation of 900 t from 2016 to 2019 in Brazil and forecast a generation of 1800 t by 2024. In addition, to define RO industrial use in Brazil as supplied by 8-inch only elements have proved to be a good approximation (2% deviation). Furthermore, the disposure rate (in elements/m³·day) of EoL-RO elements in Brazil was found as double as countries such as Spain and Australia. This indicates that operation conditions should be improved and/or that membranes are being discarded before time. Such results are important to subsidize further environmental impact assessment regarding EoL-RO in Brazil and improve production management. Finally, the proposed methodology can be easily applied to other countries whose membranes are mostly imported, as the case of developing countries.