Water treatment systems in the North Sea differ from those in the deepwater Gulf of Mexico (GOM). This paper provides a detailed understanding of these differences and provides insight into the design of water-treatment systems in general. In this study, a pilot plant with a capacity of 50 m3/d was used to conduct flotation, filtration, and adsorption trials for produced-water treatment at a crude-oil gathering facility. A recent webinar covered the varieties of current technology for flotation equipment and provided an in-depth look into flotation technology and the options surrounding offshore applications. The author reviews advances in produced water treatment, particularly offshore, since the 1960s.