WTO Cheat Sheet 2026

The 30 highest-yield WTO facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the role of the Occupational Safety and Health Administration (OSHA) in water treatment? → To enforce workplace safety standards for employees
2. A circular clarifier has a diameter of 80 feet and a water depth of 15 feet. If the plant flow is 4.0 MGD, what is the detention time in hours? → 3.37 hours
3. During the water treatment process, what is the correct sequence for coagulation and flocculation? → Rapid mixing followed by slow mixing.
4. What is the primary regulatory purpose of maintaining a chemical feed log in a water treatment plant? → To document doses applied, verify compliance, and support regulatory reporting
5. Which of the following water quality parameters is a measure of the water's ability to neutralize acids and acts as a buffer against pH changes? → Alkalinity
6. Why are water treatment operators required to have certifications? → To ensure knowledge of water quality regulations and safety procedures
7. Why are backflow prevention devices important in water distribution systems? → To prevent contamination of the water supply
8. How can water distribution systems reduce energy consumption? → By improving system efficiency and reducing friction losses
9. A gravity filter has surface dimensions of 22 feet by 30 feet. If the filter is receiving a flow of 2,300 gallons per minute, what is the filter loading rate? → 3.48 gpm/ft²
10. What type of pump is most commonly used for metering chemicals in water treatment plants? → Diaphragm metering pump
11. How can corrosion be prevented in water treatment equipment? → By using corrosion-resistant materials and coatings
12. A treatment plant processes 3 MGD and must apply 12 mg/L of alum. How many pounds of alum are required per day? → 300.24 lbs/day
13. An operator is conducting routine monitoring and finds that the pH of the finished water has dropped to 6.2. This could be a concern primarily because: → It can increase the potential for corrosion of pipes in the distribution system.
14. Which of the following factors would decrease the effectiveness of chlorine disinfection? → High pH
15. What is a common cause of water distribution system leaks? → Corrosion and pipe deterioration
16. When a 150-lb chlorine cylinder is being connected and there is risk of chlorine gas release, which personal protective equipment is required? → SCBA or supplied-air respirator with full-face protection
17. Which regulatory body enforces water quality standards in the United States? → Environmental Protection Agency (EPA)
18. Which method is commonly used to disinfect water in water treatment plants? → Chlorination
19. Which type of chemical feeder is most appropriate for feeding powdered activated carbon (PAC)? → Dry chemical feeder
20. Which of the following is a key safety practice in water treatment plants? → Using personal protective equipment (PPE)
21. Why is it important to calibrate monitoring instruments in water treatment? → To ensure accurate readings for water quality monitoring
22. Which of the following is a significant limitation of using Ultraviolet (UV) light for disinfection in a water treatment plant? → It does not provide a residual disinfectant to protect water in the distribution system.
23. What does the Safe Drinking Water Act (SDWA) regulate? → Water quality and safety standards for public systems
24. Which chemical is appropriate for neutralizing an acid spill in a water treatment plant chemical storage area? → Soda ash (sodium carbonate)
25. Which maintenance task is essential for ensuring the proper function of a water filtration system? → Cleaning and backwashing the filter regularly
26. What is the primary function of a water distribution system? → To transport treated water to consumers
27. Before beginning any maintenance work on a pump that is powered by an electric motor, what is the MOST critical safety procedure an operator must perform first? → Isolate, lock, and tag the electrical breaker for the motor.
28. In a centrifugal pump, which component is the rotating element responsible for converting motor energy into kinetic energy by accelerating the water outwards? → Impeller
29. What is the recommended frequency for inspecting mechanical equipment in water treatment facilities? → At regular intervals, as determined by manufacturer guidelines
30. What is the purpose of using ozone in water treatment? → To disinfect water and remove organic pollutants