This book is a revision of the popular study guide for water system last published in 1993. This study resource is a practical tool for treatment plant operators and distribution system personnel as they prepare for the certification exam. Actually formatting is used with the sample questions, all of which have been reviewed by ABC (Association of Board of Certification) and are based on information contained in the WSO training series Water Treatment Textbook and the Water Distributor Operation Handbook. Math formulas, conversation factors and other resource references are also included. Previous edition: 0-89867-685-1)