C-36 Plumbing Contractor License Exam Guide

The C-36 covers California plumbing — supply, waste, vent, fixtures, and gas piping.

What the C-36 exam tests

• Uniform Plumbing Code (UPC) — heavily weighted
• Drain, waste & vent (DWV) sizing
• Water supply sizing and pressure
• Gas piping (natural & LP)
• Backflow prevention
• Trade math: pitch, flow rate, fixture units

High-leverage UPC chapters

1. Chapter 4 — Plumbing fixtures
2. Chapter 6 — Water supply
3. Chapter 7 — Sanitary drainage
4. Chapter 9 — Vents
5. Chapter 12 — Fuel gas piping

Common pitfalls

• Confusing DFU (drainage fixture units) with WSFU (water supply fixture units)
• Forgetting California Green Code (CALGreen) fixture flow limits
• Underestimating gas piping sizing questions

6-week study plan

Week 1: UPC overview + diagnostic. Week 2-3: DWV systems. Week 4: water supply + gas. Week 5: backflow + safety. Week 6: full-length timed exams.