CSLB C-36 Plumbing ContractorRough-in PlumbingEasy
A plumbing contractor is installing a new water supply system for a multi-story commercial building. Which of the following materials is NOT approved for potable water distribution within the building?
- AType L Copper
- BCPVC (Chlorinated Polyvinyl Chloride)
- CPEX (Cross-linked Polyethylene)
- DGalvanized Steel
Show answer & explanationAnswer & explanation
Correct answer: D. Galvanized Steel
While historically used, galvanized steel pipe is no longer approved for potable water distribution within buildings due to corrosion, accumulation of scale, and potential for lead leaching from older coatings.
Why the other options are wrong
- A. Type L copper is a widely approved and common material for potable water systems.
- B. CPVC is an approved and common plastic piping material for hot and cold potable water distribution.
- C. PEX is an approved and increasingly common flexible plastic piping material for potable water systems.
Approved Potable Water Piping
Materials recognized by plumbing codes as safe and suitable for distributing drinking water.
- Must not leach harmful substances.
- Must withstand system pressures and temperatures.
- Common approved materials include copper, PEX, and CPVC.
Memory trick: Good pipes deliver clean water; bad pipes are a rust-filled disaster.