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CWS practice questions - frequently asked questions

Plain answers about how CWS Exam Prep works: the exam, the questions, pricing, the free trial, and what you actually get.

No - and you should be wary of any site claiming otherwise. Every question here is original, written to mirror the style, difficulty, and judgment the real CWS exam tests. Each one comes with a plain-language explanation of why the right answer is right and the others aren't.

The CWS exam spans 6 domains: Basic Water Knowledge (23% of the exam); Water Problem Diagnosis (17% of the exam); Treatment Technologies Applications (38% of the exam); Installation (6% of the exam); Service & Maintenance (4% of the exam); Regulatory (11% of the exam). Every practice question on this site is tagged to one of these domains.

The domains are not weighted equally on the exam. By share of the marks: Treatment Technologies Applications 38%; Basic Water Knowledge 23%; Water Problem Diagnosis 17%; Regulatory 11%; Installation 6%; Service & Maintenance 4%.

The CWS exam has 150 questions and is completed in 3 hours. Our timed practice mirrors that length and pacing, so exam day feels familiar.

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