Echelon Institute provides AI-powered exam preparation for US water and wastewater operators pursuing ABC/WPI certification. All content is aligned to the official 2025 WPI Need-to-Know Criteria published by Water Professionals International (WPI) and the Association of Boards of Certification (ABC).
Echelon covers all four operator certification streams: Water Treatment, Wastewater Treatment, Water Distribution, and Wastewater Collection. Each stream is available for Class I through Class IV.
Approximately 45 US states use the ABC/WPI standardized exam system. Echelon covers operators in Iowa, Colorado, Oregon, Ohio, Michigan, Wisconsin, Minnesota, Indiana, Virginia, North Carolina, Georgia, Maryland, Massachusetts, Washington, Pennsylvania, and all other WPI states. Find your state.
The WPI exam consists of 100 multiple-choice questions covering treatment processes, laboratory analysis, equipment operation and maintenance, source water quality, and safety and security. Calculation questions make up 10–16% of the exam. The passing score is 70%.
Echelon's AI tutor explains every answer in detail, identifies your weak modules, and adapts the session to focus where you need it most. Practice with 500+ questions per level, take full-length 100-question timed mock exams, and review key concepts with organized flashcards.
Echelon offers monthly and annual subscription plans. The annual plan provides the best value. View current pricing. Free practice questions are included — no account required to begin.
Select your stream and class level to begin: browse all 16 courses or find your state for state-specific certification information.