The hydrodynamics of a dyeing machine affects the exchange mechanisms between a textile material and the liquid medium to a large extent. Namely, the transfer of dyes and chemicals from the dyeing liquor and the release of non-bonded substances during subsequent rinsing steps can be altered by relative movement between phases. Such aspects have not been investigated thoroughly, although the typical approach of chemical engineering can offer a relevant contribution in this view. As a practical result, important benefits may follow in various operations of the dyeing process, aimed at optimising the equipment use or saving resources, in particular water. The attention of this study was focused on hank-dyeing machinery, since this production demands a considerable amount of water due to the large liquor ratios. The experimental study was carried out at a textile industry facility by operating on two units of equipment at significantly different scales. The rinsing operation was monitored by sampling the liquid at several positions along the vertical direction of the liquor: colour, conductivity and other chemical properties were measured in order to devise an optimal production policy aimed at saving water. A mathematical model of the equipment, based on a simple hydrodynamic hypothesis and proper mass balances, was proposed, and its outputs were compared with the experimental results. Both practical considerations and the theoretical analysis suggest that water requirement during rinsing can be halved by modifying the procedure without affecting the final quality of products.