More so than at any other time in the power plant era, water from the beginning of its journey through a plant to its discharge must be viewed holistically. This is as true for combined-cycle power plants as it is for the remaining coal units in the U.S. This article examines combined-cycle plants and their attendant heat recovery steam generators (HRSGs), where increasingly stringent wastewater regulations are forcing plant personnel to consider complex treatment methods to ensure that liquid discharge complies with regulatory guidelines. In some cases, zero liquid discharge (ZLD) may be the only option. These issues in turn are influencing other water treatment processes, most notably cooling water treatment. At plants with cooling towers, personnel may need to look beyond what have been the mainstream treatment programs. In part, increased wastewater treatment complexity has influenced some developers to select air-cooled condensers in place of the steam surface type. Finally, by choice or often mandate, many plant designers are selecting less-than-pristine water supplies, such as treated municipal wastewater, for makeup. These supplies often contain unwelcome contaminants, i...