Copper LB88
Longest proven service life, indifferent to UV and rodents, largest bore of the three and workable by anyone with a torch. Specify it where the walls will not be opened again and where the water chemistry is known to be kind to it.
Copper vs CPVC vs PEX for a repipe
Updated 2026-10-18
A repipe is the one job where the material choice is genuinely open, because everything is being replaced anyway. All three are approved, all three work, and the differences that matter are hours, bore and which failure mode you would rather live with.
Best overall
PEX-A on home runs
Fewest labour hours, no joints inside walls, and the best freeze behaviour of the three.
Best value
CPVC
Cheapest material, rigid so it supports like copper, and no specialised tool on the van.
Best for repipes you never revisit
Copper type L
Longest proven life, largest bore, immune to UV and rodents — where the water chemistry allows it.
Fixtures and repairs
The matrix
| Factor | Copper L | CPVC | PEX-A |
|---|---|---|---|
| Material per fixture | $130–300 | $45–110 | $55–130 |
| Labour hours per fixture | 3.4–5.4 | 2.2–3.6 | 2.0–3.2 |
| Inside diameter, 3/4" | 0.785" | 0.715" | 0.671" |
| Joints inside walls | Many | Many | None on a home run |
| Joining | Solder, braze or press | Solvent cement | Expansion or crimp |
| Freeze behaviour | Splits | Cracks | Often survives |
| UV tolerance | Unaffected | Poor | None |
| Works with a torch nearby | Yes | No — keep heat away | No |
| Rodent damage reported | No | Rare | Yes, in some regions |
| Service life in practice | 50+ years | 40+ years | 25+ year warranties |
Re-size, do not re-pipe
All three have different bores at the same nominal size. A drawing that says 3/4" means three different capacities. Re-run the pipe size calculator for whichever material actually goes in.
Where each one wins
CPVCD2846
Cheapest material of the three, rigid like copper so it supports the same way, and no specialised tool beyond a cutter and cement. Popular where local practice favours a rigid system.
PEX-AF876
Fewest hours, no joints inside a wall on a home run, and the best freeze behaviour of the three. The default answer on a retrofit repipe in an occupied house.
Insurers and inspectors
All three are approved potable water materials in the model codes. Insurers set their own underwriting questions, and what can come up is history: certain older polybutylene and early-generation systems carry a reputation that gets applied loosely to anything plastic. Ask the carrier what it wants to know before the material is chosen, and keep the permit sign-off and the invoice to show what went in.
The honest answer to give a customer is that the material is not the risk — the installation is. Joints inside walls, unsupported runs and UV exposure during construction cause more claims than the choice between these three.
Buying checklist
Before the material is ordered
- Occupancy checked with the AHJ: the chosen material is listed for it.
- Bore picked per material and the trunk re-sized to it — the three IDs differ.
- PEX: manifold or home-run location agreed with the owner before any wall opens; tubing kept out of sunlight on site.
- CPVC: cement in date, no torch work anywhere near the run.
- Copper: ask a plumber who works locally how the water treats copper there.
- Wall-access plan agreed: which openings, who patches, in what order.
- Shield plates priced for every stud or joist crossing closer than 1-1/4" to the face.
- Two inspections booked: pressure test with walls open, then final.