Short definition
Plastic pipe is umbrella vocabulary covering every polymer-based plumbing pipe — PVC, CPVC, ABS, PEX, PE/HDPE, polybutylene (legacy), and a handful of specialty materials. Each has different temperature and pressure ratings, different joining methods, and different approved applications. When an inspection report says “plastic pipe throughout,” ask which type — the implications differ enormously.
What it is
The major residential plastics:
- PVC — white, rigid, cold water and DWV only. Solvent-cement.
- CPVC — tan/cream, rigid, hot and cold supply. CPVC-specific solvent cement.
- ABS — black, rigid, DWV. Single-step solvent cement. Dominant in WA DWV.
- PEX — flexible, color-coded, hot and cold supply. Crimp / clamp / expansion / push-fit. Modern WA new-construction supply standard.
- PE / HDPE — black, flexible, buried water service and irrigation. Insert-and-clamp or fusion.
- Polybutylene — gray, flexible, supply pipe used 1978–1995. Banned, repipe target.
Why it matters to a homeowner
When a buyer’s inspection or insurance underwriter says “plastic pipe,” the type determines everything — PEX is universally accepted, polybutylene is a deal-killer, CPVC has known cold-snap brittleness, PVC is fine for cold and DWV but not hot supply. Get specific before reacting to the umbrella term.