The main objective of the present study is to prioritize those pharmaceuticals that have higher chances to be detected in water due to incomplete removal in Wastewater Treatment Plants (WWTPs). To do so, the total consumption of pharmaceuticals in Catalonia (NE Spain) were compiled to calculate the predicted environmental concentrations (PECs) in wastewater effluents and in river water. PECs were estimated using publicly available consumption data in the period of 2013–2016 for a suite of 165 compounds. The selected compounds were based on generic pharmaceuticals with emphasis on drugs consumed by people aged 65 or over as they represent the age group with the highest consumption of pharmaceuticals. The mean total consumption of pharmaceuticals in the period studied was of 623 ± 3 t per year. Paracetamol, metformin and ibuprofen were the most administered drugs although the highest PEC values corresponded to metformin, amoxicillin and metamizole. Finally, predicted environmental levels together with acute and chronic toxicological data allowed estimating the risks of these compounds. Amoxicillin is expected to pose adverse effects for cyanobacteria, whereas metformin and ibuprofen pose a small potential for adverse effects to invertebrates and fish, respectively.