The Guide to Hydrothermal Spa Development Standards is published by the Global Wellness Institute and was created to provide design and building guidelines for hydrothermal areas (also known as wet areas ) in spas and private residences. Hydrothermal bathing (including saunas, hamams, steam rooms, hydrotherapy pools, etc.), with its benefits of cleansing, detoxifying and improving the immune system, dates back thousands of years and is one of the most ancient spa practices. The goal of this guide is to provide readers - whether they be spa owners, consultants, developers, interior designers, architects, builders, professors, students or anyone embarking on the study or build of a hydrothermal facility - with a consistent and effective means to approach the planning and construction of these unique areas and to avoid common, costly mistakes.