The Washington Application for Backflow Specialty Exam is a certification exam administered by the Washington State Department of Health (DOH) in order to ensure that plumbing professionals are qualified and competent in the installation, maintenance, and repair of backflow prevention devices. The exam is divided into three different types: the Cross-Connection Control Specialist Exam, the Backflow Prevention Assembly Tester Exam, and the Certified Backflow Prevention Assembly Tester Exam. The Cross-Connection Control Specialist Exam covers the concepts of cross-connection control, backflow prevention, and backflow prevention assembly testing. The Backflow Prevention Assembly Tester Exam focuses on the installation, maintenance, and repair of backflow prevention assemblies and devices. The Certified Backflow Prevention Assembly Tester Exam requires additional experience in backflow prevention assembly testing and covers advanced concepts and techniques. All three exams require applicants to demonstrate a thorough understanding of the plumbing codes, regulations, and industry standards related to backflow prevention. Applicants must also complete an application and submit the appropriate fees.