PC Study Guide 2026
Everything you need to pass the PC exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 PC Exam Format at a Glance
📚 PC Topics to Study (69)
✍️ Sample PC Questions & Answers
1. What is the recommended maintenance interval for lubricating the packing nuts on gate valves in a commercial plumbing system?
Annual lubrication of packing nuts prevents stem corrosion and ensures gate valves can be fully opened or closed when needed.
2. A copper supply line is found to have pitting corrosion on its interior surface. This type of corrosion is MOST commonly associated with:
Low pH (acidic) water aggressively attacks copper pipe interiors, causing pitting corrosion that eventually leads to pinhole leaks.
3. What does a pipe bender's 'take-up' measurement account for?
Take-up (also called gain or shrinkage) is subtracted from the measured distance so the bent pipe ends up the correct length after the curve is formed.
4. A plumber needs to install a sanitary tee fitting in a drainage system. In which orientation is a sanitary tee allowed to be installed?
Sanitary tees may only be installed in the vertical position on drainage systems; horizontal installations require a wye and 1/8 bend combination.
5. What is the role of documentation in Preventive Maintenance Procedures for Plumber Certification?
Proper documentation in Preventive Maintenance Procedures ensures accountability, traceability, and serves as a reference for future decisions.
6. A newly installed backflow preventer on an irrigation system repeatedly loses prime and allows water to back-siphon. The MOST likely cause is:
Debris lodged in the check valve seats of a backflow preventer prevents the valves from sealing, allowing back-siphonage under low or negative pressure conditions.