California T4 Water Treatment Operator Practice Test
Expert practice for the California SWRCB DDW T4 Water Treatment Operator certification — the second-highest grade in California's five-tier treatment ladder, for large/complex systems. Builds on T3 with pump-curve interpretation, advanced treatment (GAC/RO/ozone), LCRR LSL Inventory, capital planning, asset management, drought/wildfire/seismic resilience, integrated plant math, and large-system operations management. Calibrated to California DDW Drinking Water Treatment Exam Expected Range of Knowledge rev. April 2020.
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Browse all testsBoth options pull from the same 70-question bank. The quick quiz randomly selects 25 questions each time you take it.
California T4 Water Treatment Operator Practice Test
About this practice test
This California T4 Water Treatment Operator Practice Test practice test is a free study tool for water operators preparing for state and national certification exams. The 70 questions on this exam cover the most common topics tested at this level, and every question comes with a plain-English explanation so you can actually learn the material.
If you're studying for the certification exam, we recommend taking this test once, reviewing the explanations for any questions you missed, and then taking it again later. You can also explore the other practice tests covering specific topics like disinfection, filtration, and operator math. If you want a structured walk-through of what to study and in what order, see our 30-day study plan.