Szeto Plumbing · San Gabriel Valley
Copper or PEX for your repipe
Repiping an older San Gabriel Valley house? How copper and PEX compare on hard water, installation, noise and longevity, and which fits your walls and attic.
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Kitchens, baths, heaters, main lines
Updated · 3 min read
Short answer
Both copper and PEX are solid choices. Copper is rigid, heat-tolerant and familiar; PEX is flexible, fast to route through finished walls and resists freeze splits. Hard water, wall access and personal preference usually decide it.
On this page
Why repipes come up here
Housing in the western SGV is mostly postwar. Census medians run from 1957 in San Gabriel to 1963 in Monterey Park.
Original galvanized supply pipe in many of these houses is past its useful life, and older copper can develop pinholes.
Hard water and each material
Very hard water forms scale in both. Copper can develop pinholes from high velocity; PEX does not corrode but its fittings can collect scale.
Routing in your house
Raised-foundation houses let new lines run in the crawlspace. Slab houses usually route through the attic and drop down walls.
PEX's flexibility means fewer wall openings in finished rooms. Copper needs straighter runs and more fittings.
Other things to weigh
- PEX should be kept out of direct sunlight
- Copper is often preferred at the water heater connection
- Mixed systems, PEX in walls and copper at the heater, are common
Common questions
Does PEX affect water taste?
Certified PEX is made for drinking water. Some people notice a slight taste at first, which fades.
Is copper noisier?
Copper transmits sound and water hammer more. Proper strapping reduces noise.
Can a repipe be done one bathroom at a time?
Yes, though whole-house repipes avoid mixing old and new pipe.