Treatment processes jump from 25 to 35 questions. Grade 3 also opens the Advanced Water Treatment Operator (AWT3) exam.
California's certificate for running a drinking water treatment plant.
Start studying T3| Content area | questions of 100 | |
|---|---|---|
| Source Water | 20 | |
| Water Treatment Processes | 35 | |
| Operation / Maintenance | 15 | |
| Laboratory Procedures | 15 | |
| Regulations / Administrative Duties | 15 |
59% of examinees passed (174 of 293) from July 1, 2025 to June 30, 2026. Source: SWRCB Drinking Water Operator Certification Program, Water Treatment Exam Results (through 6/30/2026). The agency updates these tables every six months.
Filtration: loading rate · an original practice item written only from publicly available sources, not a real exam question
A gravity filter bed measures 20 ft by 25 ft and receives 2,000 gallons per minute (gpm). What is the filtration rate?
A. 4.0 gpm/ft²
Filter area = 20 ft × 25 ft = 500 ft². Filtration rate = 2,000 gpm ÷ 500 ft² = 4.0 gpm/ft². 44.4 adds the two sides (2,000 ÷ 45) instead of multiplying them, and 80 and 100 divide by a single side length instead of the area.
Free, no account, and progress stays in your browser.
Topic coverage follows Expected Range of Knowledge for Drinking Water Treatment Exam (SWRCB Division of Drinking Water, rev. 4/2020). Practice questions are written only from publicly available sources (that outline and the regulations and references it cites); they are not real exam questions, which are confidential. Check current application requirements, fees and exam dates on the certifying body's own page: official certification page.
Questions, flashcards, and explanations are AI-written from publicly available sources only: the exam content outlines and candidate materials each certifying body publishes without restriction, and the regulations and technical references they cite. No confidential material is used, including actual exam questions, recollections of any exam sat by the author, or any handbook or document released under a confidentiality agreement. Content is then put through repeated review — regulatory values checked against primary sources, every calculation recomputed, and errors corrected — plus spot checks by the author, who holds California water operator certifications and a California civil engineering licence. Those spot checks are sampling, not a professional review: nothing here is stamped, sealed, or offered as engineering advice, and not every item has been individually verified, so mistakes can still slip through.