In this paper, we discuss the advantages and drawbacks of POCIS (Polar Organic Chemical Integrative Sampler) for the evaluation of river water quality downstream of wastewater treatment plants. POCIS proved well adapted to sampling alkylphenols and several pharmaceuticals. Concentration factors and the decrease in limits of quantification, compared to grab water sample analyses, were significant except for hormones, β-blockers and bronchodilators. Promising preliminary results obtained in situ on deuterated atenolol used as a performance reference compound need to be confirmed in-lab. This work confirms that POCIS is a valuable tool for monitoring hydrophilic organic molecules in river and wastewaters.