Trade Exam · Module 2
Code Awareness in Planning
Before you price a plumbing job you need to know what the California Plumbing Code will require of it: whether a permit is needed, which fixture flow limits apply, how pipes are sized, what venting must do, which inspections and tests come when, and which code items (pressure regulators, expansion tanks, seismic straps) belong in the price. This lesson covers those planning-level rules with the 2025 CPC section behind each one.
Key Takeaways
- The 2025 California Plumbing Code is Part 5 of Title 24 and adopts the 2024 Uniform Plumbing Code with California amendments (CPC 1.1.1).
- Permits: CPC 104.1 requires one to install, alter, repair, replace or remodel a plumbing system; 104.2 exempts only stopping leaks and clearing stoppages without replacing valves, pipes or fixtures. Your local jurisdiction administers permits.
- Flow limits: water closets 1.28 gpf (411.2); showerheads 1.8 gpm at 80 psi (408.3); residential lavatory faucets 1.2 gpm at 60 psi (407.2.2); sink faucets 2.2 gpm at 60 psi (420.2); kitchen faucets 1.8 gpm at 60 psi (420.2.1).
- Drain pipes are sized with drainage fixture units (Tables 702.1 and 703.2); water piping with water supply fixture units (Table 610.3).
- Every fixture trap must be protected by venting (901.2). Vents end at least 6 inches above the roof and 12 inches from a vertical surface (906.1).
- The three required inspections are underground (before backfill), rough-in (before wall or ceiling membranes) and final (CPC 105.2). Nothing may be covered until inspected and approved (105.1).
- Static pressure over 80 psi requires a pressure regulator, and an expansion tank downstream of it (608.2).
Why This Matters
CSLB's C-36 study guide lists "scope of work and code compliance," "pipe sizing and venting requirements," "job site inspections" and "water conservation" as subjects in Planning and Estimating, about 22 percent of the trade exam. Code questions test specific numbers, so learn the key figures in this lesson along with the reasons behind them.
In planning, code awareness is about money and schedule. A code item you miss in the estimate is a cost you absorb. An inspection you miss in the schedule is work you tear out.
What the California Plumbing Code Is
The 2025 California Plumbing Code (CPC) is Part 5 of Title 24 of the California Code of Regulations, the California Building Standards Code. Section 1.1.1 says it adopts the 2024 Uniform Plumbing Code published by IAPMO, with California amendments. It covers water supply, sanitary drainage, venting, indirect waste, storm drainage, fuel gas piping, water heaters and alternate water sources, among other things.
Some sections carry agency tags such as [HCD 1] or [BSC-CG]. Those tell you which state agency adopted the amendment and which buildings it applies to (for example, HCD for most residential buildings).
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