With the aim of improving the physicochemical and organoleptic quality of the water supplied to Barcelona metropolitan area from the River Llobregat, a pilot plant was built to test the behaviour of reverse osmosis and electrodialysis reversal techniques, in three different designs or scenarios. This study was focused on flavour analyses carried out on several blends in different proportions of water treated by membranes and by conventional treatment. The tasting was performed by trained panelists. The sensory techniques used included acceptance tests (ranking and rating) and discrimination tests (triangle difference). The statistical tools used in the data analysis were first ANOVA and Friedman analysis for rating and ranking tests. respectively, followed by the corresponding least significant difference test in both cases. The results of the triangle tests were consistent with the previous tests. The results obtained reveal the significant improvement in the water flavour provided by both membrane techniques. In some cases this improvement was already perceptible with a proportion of membrane water of only 30% and the blends equalled, or even in some cases exceeded. the assessment of the water from the River Ter, the other important resource of the area and which is taken as a reference of water highly valued by the consumer. (C) 2009 Elsevier B.V. All rights reserved.