Currently, environmental regulations induce industrialists to implement source reduction techniques in order to comply with the prevention principle toward sustainable development. The project PIPSI (PIlotage Propre des Systegravemes Industriels/industrial system clean piloting) financing by Rhone-Alps Region is carried out with the aim to contribute to this objective. The study presented in this article concerns the pollution transfer in a metal finishing treatment line in order to minimise the environmental impact obtained notably with the pollution balance. Drag-out and draining phenomena have been particularly studied. Results obtained showed that a 10 seconds of draining reduced drag-out from 65 to 85% in terms of pieces design. Moreover, during the experiments, 5 drag-out levels were identified by medium values from 26 to 1700 ml m-2. So that, either a piece can be associated to a level or knowing the piece drag-out level, it is possible to evaluate its medium drag-out value. Then the pollution balance will be obtained more easily.