CSLB C-36 Plumbing ContractorRough-in PlumbingMedium
A plumbing contractor is installing a new water supply system for a multi-story commercial building. Which of the following materials is generally NOT permitted for potable water distribution piping within the building according to current California Plumbing Code (CPC) standards?
- ACopper tubing (Type L or K)
- BGalvanized steel pipe
- CCPVC pipe
- DPEX tubing
Show answer & explanationAnswer & explanation
Correct answer: B. Galvanized steel pipe
While historically used, galvanized steel pipe is generally not permitted for new potable water distribution systems in California due to corrosion issues, which can lead to reduced flow and water quality problems over time. The CPC has largely phased it out for new installations.
Why the other options are wrong
- A. Copper tubing (Type L or K) is a widely accepted and common material for potable water systems.
- C. CPVC (chlorinated polyvinyl chloride) pipe is an approved plastic piping material for potable hot and cold water distribution.
- D. PEX (cross-linked polyethylene) tubing is a common and approved material for potable water supply systems.
Potable Water Pipe Materials
Approved materials for conveying drinking water safely within a building's distribution system, adhering to health and safety standards.
- Must not leach harmful substances into water.
- Resistant to corrosion and degradation.
- Approved by local plumbing codes (e.g., CPC).
Memory trick: Copper, PEX, CPVC are Clear; Galvanized is Gone for Good.