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Realistic practice questions, timed mock exams and clear explanations for the certification exams that get you hired — starting with EPA 608, CDL, and water operator licensing.
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- Explanation for every answer
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5
exams
241
practice questions
7
certification areas
Popular exams
Start with the exams most technicians, CDL applicants and operators are preparing for.
Commercial Driver's License (CDL) Knowledge Tests
Federal knowledge tests for Class A, Class B and Class C: General Knowledge, Air Brakes, Combination Vehicles, plus Hazmat, Tanker and Passenger endorsements.
- Questions
- 95questions
- Mock exams
- 6topics
- Difficulty
- Intermediatedifficulty
EPA 608 Technician Certification
Federal certification required to buy refrigerant and service stationary air-conditioning and refrigeration equipment. Covers Core, Type I, Type II and Type III.
- Questions
- 104questions
- Mock exams
- 4topics
- Difficulty
- Intermediatedifficulty
Wastewater Collection System Operator — Grade 1
Entry-level certification for operators who maintain sewers, manholes, and lift stations. Covers pipe materials, inspection and cleaning, lift station operation, infiltration and inflow, confined space safety, and the math behind pipe volume and slope.
- Questions
- 14questions
- Mock exams
- 5topics
- Difficulty
- Intermediatedifficulty
EPA 608 study guides
The pages technicians search before they book: Universal, taking it online, which type you need, and the 72% passing score.
Universal certification
Core + Type I, II and III. 100 questions, 72% on each section — the card most shops want.
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Take EPA 608 online
Live proctor from home. Same exam as a testing center. EPA does not give the test itself.
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Type 1 vs Type 2 vs Type 3
Small appliances, splits and chillers are three different cards. Universal is all three plus Core.
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Passing score: 72%
18 of 25 on each section — not an overall average. Fail Core and you take home nothing.
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Who needs EPA 608
If you open a refrigerant circuit or buy cylinders, you need 608. Cars are 609.
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CDL practice tests
General Knowledge, Air Brakes and endorsements — plus the state pages people search before they book DMV.
Free CDL practice test
Original questions on General Knowledge, Air Brakes, Combination Vehicles, Hazmat, Tanker and Passenger.
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Class A vs Class B vs Class C
Trailer 10,001 lb+ is A. Single heavy truck is B. 16+ riders or placards can be C.
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CDL permit (CLP)
Pass the knowledge tests, wait (often 14 days), practice with a qualified CDL holder, then skills.
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Passing score: 80%
Each test is scored alone. 40 of 50 on General Knowledge. Fail Air Brakes and you get a restriction.
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California CDL
CA DMV knowledge tests on the federal topics. Practice here, then book DMV.
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Texas CDL
Texas DPS written tests. Same General Knowledge, Air Brakes and Class A combination bank.
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Florida CDL
Florida DHSMV knowledge tests. Drill 80% before you sit at the tax collector.
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Georgia CDL
Georgia DDS written tests. Class A still needs Combination Vehicles — do not skip it.
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Browse by certification area
Commercial Driving
CDL knowledge tests: General Knowledge, Air Brakes, Combination Vehicles and endorsements.
1 exam available
HVAC & Refrigeration
EPA 608, NATE, and state HVAC licensing exams.
1 exam available
Water & Wastewater
Treatment, distribution and collection system operator certifications.
3 exams available
Security
Unarmed and armed security guard licensing exams.
Coming soon
Pesticide Applicator
Core and category exams for commercial and private applicators.
Coming soon
Pool & Spa
Certified Pool Operator and aquatic facility operator exams.
Coming soon
Electrical & Plumbing
Journeyman and master trade licensing exams.
Coming soon
How it works
- 1
Choose your exam
Pick the certification you're sitting for and see exactly which topics it covers and how they're weighted.
- 2
Practice by topic
Answer questions in quick sets or drill one category. Every answer shows why it's right and where the rule comes from.
- 3
Take a mock, fix weak spots
Sit a timed mock exam, then let your dashboard point you at the categories that are costing you points.
Why technicians choose CertReady
Written for the real test
Questions target the numbers, dates and traps that actually appear — not filler.
Timed like the real thing
Mock exams match the section length and pacing of the official exam.
Know where you stand
Category-level scores and streaks show whether you're ready to book the exam.
Honest and independent
Original material, clear sourcing, and no claims of official affiliation.
Frequently asked questions
- Is CertReady free?
- Yes. Every exam has a free practice tier with explanations and mock exams. A premium tier with the full question bank and deeper analytics is planned; nothing is charged today.
- Are these the actual exam questions?
- No. All questions are original practice material written to mirror the topics and difficulty of the official exams. CertReady is not affiliated with any certifying organization.
- Do I need an account?
- You can practice a limited set of questions without an account. A free account saves your progress, bookmarks, test history and weak-topic analysis across devices.
- Which exams are available?
- EPA 608 (Core, Type I, II and III), CDL knowledge tests (General Knowledge, Air Brakes, Combination Vehicles, Hazmat, Tanker and Passenger), and Grade 1 water and wastewater operator exams.
Ready to pass on the first try?
Create a free account to save your progress, bookmark tricky questions and track your weak categories.