CA Plumbing PrepC-36 License Exam Prep
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Trade Exam · Module 5

Fixture and Water Heater Replacement

Lesson 8 of 10~20 minFree previewCurrent as of September 2026Leer en español

Swapping a toilet, faucet, shower valve or water heater is everyday service work, and the replacement has to meet today's code even when the house is old. This lesson walks you through a clean replacement and the 2025 California Plumbing Code rules that apply: clearances, flanges, control valves, connector lengths, flow limits, scald protection, and water heater strapping, connectors, relief discharge and gas connections.

Key Takeaways

  • Replacing a fixture is not on the CPC 104.2 exempt list, so a permit is required unless the local jurisdiction exempts it; water heater replacement also needs a permit.
  • New fixtures must meet current flow limits: water closets 1.28 gpf (CPC 411.2), showerheads 1.8 gpm at 80 psi (CPC 408.3), residential lavatory faucets 1.2 gpm and kitchen faucets 1.8 gpm at 60 psi (CPC 407.2.2, 420.2.2).
  • A water closet needs at least 15 inches from its center to a side wall, 30 inches center to center, and 24 inches clear in front (CPC 402.5); the closet flange sits on top of the finished floor (CPC 402.6).
  • Each fixture supply gets a control valve ahead of the slip joint or appliance supply (CPC 606.5); corrugated metal fixture connectors are limited to 30 inches (CPC 604.12).
  • A replacement shower or tub-shower valve must be a pressure balance, thermostatic or combination type limited to 120 F at the outlet (CPC 408.4, 408.4.2).
  • Water heaters are strapped within the upper and lower thirds, with the lower strap at least 4 inches above the controls (CPC 507.2); state law applies this to new, replacement and existing residential heaters (H&S Code 19211).
  • Metal flexible water heater connectors are limited to 24 inches, and PEX or PE-RT may not be used in the first 18 inches from the heater (CPC 604.13).
  • Gas appliances connect by rigid pipe, semirigid tubing, CSST or one listed connector in the same room (CPC 1212.1), with a shutoff within 6 feet (CPC 1212.6) and a sediment trap (CPC 1212.9).

Why This Matters

Fixture and water heater replacements fall under both the Finish Plumbing Installations section (plumbing fixtures and appliances, water heaters, shut-off valves) and the Service, Repair, and Remodel section of the CSLB C-36 exam. On the job, a replacement is new work: the new fixture and its connections must meet the current code.

Permits

CPC 104.1 requires a permit to install, alter, repair, replace or remodel a plumbing system except for the work listed in CPC 104.2. The exempt list covers clearing stoppages (including pulling and resetting a water closet) and repairing leaks without replacing or rearranging valves, pipes or fixtures. Replacing a fixture or a water heater is not on that list. Chapter 1, Division II is adopted locally, and many building departments exempt or simplify some like-for-like swaps, so check the local rules before you quote the job. For housing under HCD, CPC 1.8.4.1 lets the enforcing agency exempt minor changes that do not affect structural features, egress, sanitation, safety or accessibility.

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