The Grade IV exam runs 4 h with 64 items worth 128 points, and passing needs both 70% overall and at least half of the math points.
No true/false section; essay-style items appear in volume.
The certificate for operating a wastewater treatment plant in California, issued through the State Water Resources Control Board's Wastewater Operator Certification Program.
Start studying Grade IV| Education | Qualifying experience |
|---|---|
| High school + 32 educational points | 6 years |
| Associate degree or 60 units incl. 15 science units | 4 years |
| Bachelor's or higher incl. 30 science units | 3 years |
| Registered chemical, civil or mechanical engineer | 2 years |
| Item type | Count and points |
|---|---|
| multiple choice | 25 items at 2 points each |
| multiple-choice essay | 24 items at 2 points each |
| math | 15 items at 2 points each |
31% of examinees passed (26 of 85) from July 1, 2025 to June 30, 2026. Source: SWRCB Wastewater Operator Certification Program, Wastewater Treatment Exam Results (updated 8/12/2026). The agency updates these tables every six months.
Management: energy savings · an original practice item written only from publicly available sources, not a real exam question
An aeration blower draws 150 hp of electrical power around the clock. Dissolved oxygen control is expected to cut that draw by 30%. At $0.16 per kWh, what is the expected annual saving?
B. $47,100
150 hp × 0.746 = 111.9 kW. A 30% cut saves 33.6 kW, and over 8,760 hours a year that is 294,100 kWh × $0.16 = about $47,100. $156,800 is the blower's whole annual cost, $63,100 prices horsepower as kilowatts, and $129 is one day's saving.
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Topic coverage follows WWTP Operator Examination Information (SWRCB Wastewater Operator Certification Program — per-grade documents). 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.