The Florida Plumbing Trade Knowledge Exam
The Plumbing Trade Knowledge exam is a required part of the Certified Plumbing Contractor license in Florida. It is open book, like every Florida CILB exam, so the tested skill is as much knowing where to find an answer as knowing it cold.
- 110
- Questions
- 9 hr
- Time limit
- 70%
- To pass
- Open book
- Format
What's on the Trade Knowledge exam
The exam follows the official DBPR content outline. These are its weighted domains — study time is best spent where the exam puts its points.
Water Supply & Distribution
Sizing, pressure, backflow prevention, water heaters — plus pools, wells, and irrigation.
Drainage, Waste & Vent
DWV sizing, traps, vents, slopes, and cleanouts.
Fixtures & Appliances
Fixture units, installation clearances, and accessibility basics.
Fuel Gas Piping
Gas pipe sizing concepts, materials, testing, and venting.
Specialty Piping Systems
Medical gas (NFPA 99), industrial piping, solar thermal, and fire protection (NFPA 14) — 40% of the official outline.
Code Compliance & Isometrics
Florida Plumbing Code navigation, isometric reading, and inspections.
Sample questions
Original, exam-style questions with the answer and an explanation — a taste of how LicenseReady drills the Trade Knowledge material.
Which method of backflow prevention is considered the most reliable protection against contamination of a potable water supply?
An air gap
An air gap is a physical, unobstructed vertical separation between the water outlet and the flood level rim of the receiving fixture. Because it has no moving parts that can fail or stick, it is regarded as the most reliable means of backflow prevention.
Source: Florida Building Code — Plumbing — Protection of Potable Water Supply
A potable water line supplies a chemical mixing tank where backpressure could force toxic chemicals into the water supply. Which mechanical backflow preventer is appropriate for this high-hazard application?
A reduced pressure zone (RPZ) backflow preventer
A reduced pressure zone assembly uses two independent check valves with a relief valve between them that discharges to atmosphere if either check leaks. It is the mechanical device specified for high-hazard cross-connections where a health hazard exists under backpressure or backsiphonage.
Source: Florida Building Code — Plumbing — Backflow Prevention Devices
Reference books you'll use
The Trade Knowledge exam is open book. These are the approved references its questions come from — tabbing them in advance is half the battle.
Plumbing References
Plumbing code questions are chapter questions: water supply, DWV, vents, and fixtures each live in their own chapter. Learn the chapter map and the definitions chapter cold.
Florida Building Code
Code questions give themselves away with words like 'minimum', 'required', or 'permitted'. Go to the code — never answer a code question from memory when the book is on the desk.
Frequently asked questions
How many questions is the Florida Plumbing Trade Knowledge exam?
110 questions. You have 9 hours and need 70% correct to pass.
Is the Plumbing Trade Knowledge exam open book?
Yes. Every Florida CILB construction exam is open book — you bring approved, tabbed reference books. The challenge is finding answers fast enough, which is why pacing and tabbing matter as much as knowledge.
What topics are on the Trade Knowledge exam?
The exam is weighted across 6 domains: Water Supply & Distribution, Drainage, Waste & Vent, Fixtures & Appliances, Fuel Gas Piping, Specialty Piping Systems, Code Compliance & Isometrics. Heavier-weighted domains deserve more study time.
LicenseReady is an independent exam-preparation service. We are not affiliated with, endorsed by, or approved by the Florida Department of Business and Professional Regulation (DBPR), the Construction Industry Licensing Board (CILB), or Professional Testing, Inc. All practice questions are original content created by LicenseReady — they are not actual examination questions. Exam-structure information comes from publicly available DBPR publications. Third-party product names (AIA, ACCA, and others) are trademarks of their respective owners, used only to identify the referenced works.