The SWRO market has become more competitive and the cost gap between the winning and the unsuccessful bid observed in recent tenders can be a matter of only a few cents. This underlines the importance of cost reduction as one of the main designer goals and emphasizes the search for innovative solutions to gain advantage over competitor offers. In this paper a techno-economical study will be presented, evaluating the impact of varying the number of elements per vessel. Possible technical trends will be described and conclusions drawn.