Parallel multi-stage washing does not save very much water, because water is supplied to the individual baths separately. Multi-stage counterflow washing is most common in plating plants. In this method, water is supplied to the final bath and sent to the previous bathes in turn.
Water discharge is from the first bath.
Compared with parallel multi-flow washing, this method saves water efficiently. When water has been supplied to all baths, water is stopped and no more water is supplied. Washing is performed while contamination concentration in the water is monitored. The first bath is drained regularly or irregularly, to which water is sent from the second bath. The second bath is then filled with water that has been in the third bath.