Short answer
Neither is better for every house. Copper has a long record of service and tolerates heat and sunlight well. Plastic pipes, especially PEX, are generally cheaper and faster to install and are more forgiving in freezing conditions. The right choice depends on your local code, your water, the layout of the house, your budget and the plumber’s experience. For most renovation work today, PEX is a common choice, but copper remains widely used and perfectly sound where it is already installed.
Quick comparison
| Factor | Copper | PEX | CPVC |
|---|---|---|---|
| Material cost | Generally higher | Generally lower | Generally low to moderate |
| Installation | Soldered or fitted joints, more labor | Flexible, fewer joints, crimp or expansion fittings | Rigid, solvent-welded joints |
| Freeze tolerance | Can split | Better, though it can still be damaged | Can crack |
| Heat and sunlight | Handles both | Must be protected from UV | Handles hot water, protect from UV |
| Corrosion | Can pit or corrode with some water chemistry | Does not corrode | Does not corrode |
| Code acceptance | Widely accepted | Widely accepted, but check locally | Widely accepted, but check locally |
Costs and lifespans vary by region and installer, so treat the table as general guidance and get local quotes.
Copper pipe
Pros
- Long track record, and many installations last for decades
- Handles high temperatures and is not damaged by sunlight
- Rigid, so it stays in place and looks tidy where exposed
- Not permeable to oxygen or chemicals in soil
Cons
- Material and labor cost more, and prices have varied with the copper market
- More joints mean more potential leak points, and soldering requires skill and an open flame
- Some water chemistry, such as very acidic or aggressive water, can cause pinhole leaks over time
- Can split if water inside freezes
PEX
PEX is cross-linked polyethylene tubing. It comes in flexible coils and is usually joined with crimp, clamp or expansion fittings.
Pros
- Flexible, so it snakes through walls with fewer fittings
- Generally quicker and cheaper to install
- Does not corrode and tends to resist pinholes
- More tolerant of freezing than rigid pipe, although it is not freeze-proof
Cons
- Damaged by prolonged UV exposure, so it needs to be protected outdoors and during storage
- Not suited to some uses, such as direct connection to a gas water heater without proper fittings, or exposure to certain chemicals and some pest damage
- Fittings can restrict flow slightly compared with larger copper fittings
- Needs correct tools and technique, and some code rules differ by area
CPVC and PVC
CPVC is a rigid plastic rated for hot and cold water. PVC is generally used for drains and cold-water lines in some applications, but is not suitable for hot water. Both are joined with solvent cement. They are lightweight and resist corrosion, but can become brittle with age or heat and are more prone to cracking when stressed. Check which types your local code allows before buying.
Why many plumbers moved away from copper
Plumbers did not stop using copper altogether, but plastic became more common for several reasons: copper prices rose and fluctuated, plastic is faster to install, and PEX needs fewer fittings. Labor savings matter in new construction and repipes. Some water conditions are also harder on copper. Copper is still used often, particularly for exposed runs and where homeowners prefer it.
Which is healthiest for drinking water?
All approved potable water pipes are intended to be safe for drinking water. Look for pipe certified to a recognized standard for drinking water systems, such as NSF/ANSI 61 in North America. Copper can leach into water in some conditions, such as newly installed pipe or very acidic water, and some people notice a taste with new plastic pipe, which typically fades. If you have concerns, a water test can show what is in your water. Very old homes may also have lead pipes or lead solder, which is a serious health concern. If your home is old enough that lead service lines or lead solder are possible, have your water tested and consult your water utility or a qualified professional about replacement.
Should you replace working copper with PEX?
Usually not, if the copper is sound. Replacing is a significant expense and may mean opening walls. Consider it when:
- You have repeated pinhole leaks or visible widespread corrosion
- The pipe is damaged or your water chemistry is attacking it
- You are already doing major renovation with open walls
- A plumber recommends it after inspecting the system
For the full process and cost factors, see replumbing a house.
Check local code and hire the right pro
Building codes differ by location in what materials they allow and how work must be done. A licensed plumber will know what is accepted and whether a permit and inspection are needed. Mixing materials needs correct transition fittings, particularly between copper and other metals, to avoid problems. If you see signs of leaks, our guide to the signs of a leaking pipe is a good place to start.