What PEX pipe means
PEX is flexible cross-linked polyethylene tubing for water supply lines, joined with crimp, clamp or expansion fittings.
Also called cross-linked polyethylene.
Where it matters on a plumbing job
PEX makes repipes faster and cheaper than copper and handles freezing better, which is why it dominates new work. Name the fitting system on the estimate, since tools and fittings are not interchangeable between them.
What the model code says
- The code lists cross-linked polyethylene (PEX) under standards including ASME A112.4.14 and NSF 359. (IRC 2021, Chapter 29)
Check which code edition your building department enforces for PEX pipe before you quote.
What it costs
Koira's main water line replacement cost guide puts a typical job at $1,700, with most between $1,200 to $10,000. The guide shows its sources and what moves the price.
Work it out
- Cost guide: Main water line replacement cost
- Licensing: Plumbing license rules by state
- Tools, templates and guides: Free plumbing resources
Sources: 2021 International Residential Code, Chapter 29, Water Supply and Distribution (ICC). Checked October 9, 2026.