Pipe Material Comparison: Copper vs PEX vs CPVC vs PVC

The five materials you actually specify, compared on the things that decide the choice: temperature limit, pressure rating, flow smoothness, cost and what code will accept.

Hot water: copper, PEX or CPVC | Cold & DWV: PVC | Gas: black iron only

Side-by-Side Comparison

Material	Service	C-Value	Max Temp	Pressure @ 73°F	Pressure @ 180°F	Service Life	Cost
Copper	Hot & cold supply	140	400°F	200 PSI (1/2" – 2", Type L)	200 PSI	50–70+ years	$$$$
PEX	Hot & cold supply	150	180°F	160 PSI	100 PSI	—	$$
CPVC	Hot & cold supply	150	180°F	400 PSI	100 PSI	—	$$$
PVC	Cold supply & DWV	150	140°F	450 PSI (1/2") down to 280 PSI (4")	—	—	$
Black iron	Fuel gas only	100	—	7" WC residential, 14" WC and above commercial	—	—	$$$

C-value is the Hazen-Williams coefficient — higher is smoother, which means less friction loss over a long run. Cost is relative material cost, not installed cost. A dash means the source data does not state a figure for that material rather than zero.

Choosing by Application

Hot & cold supply

Copper — Highest material cost; also the highest labour skill requirement
PEX — Lower cost than copper; fewer fittings reduce labour further
CPVC — More expensive than standard PVC, cheaper than copper

Cold supply & DWV

PVC — Cheapest of the five; lightest to handle

Fuel gas only

Black iron — More expensive than plastic gas pipe, plus threading labour

Detail by Material

Copper Pipe (Type L)

Hot & cold supplyC=140 · Soldering or press fittings

Withstands up to 400°F; no degradation at plumbing temperatures

Advantages

Excellent durability (50–70+ year lifespan)
High temperature resistance
Smooth interior (C=140) for efficient flow
Resistant to most corrosion

Limitations

Higher initial cost than plastic alternatives
Requires skilled installation (soldering / press)
Can be affected by aggressive water conditions
Heavier than PEX or PVC

Code: Approved by all major plumbing codes (IPC, UPC, local). Type L is standard for water supply; Type M has a thinner wall and lower pressure rating.

Size it: Pipe Sizing Calculator →

PEX Pipe

PEX-A vs PEX-B →Hot & cold supplyC=150 · Crimp, clamp or expansion fittings

180°F continuous, up to 200°F for short periods

Advantages

Excellent flexibility — fewer fittings needed
Freeze-resistant (expands up to 3× diameter without bursting)
Smooth interior (C=150) for efficient flow
Lower cost than copper

Limitations

Not suitable for outdoor exposure (UV degradation)
Cannot be direct-buried without protection
Requires special tools for installation
Not recyclable like copper

Code: Approved by IPC, UPC and most local codes for water supply. Some jurisdictions restrict PEX in specific applications — verify with your AHJ.

Size it: Pipe Sizing Calculator →

CPVC Pipe (Schedule 40)

Hot & cold supplyC=150 · Solvent welding (CPVC-specific cement)

180°F continuous, up to 200°F for short periods

Advantages

Suitable for hot water (up to 180°F)
Lower cost than copper
Smooth interior (C=150) for efficient flow
Easy installation (solvent welding)

Limitations

More expensive than standard PVC
Requires CPVC-specific fittings and cement
Not suitable for outdoor exposure (UV degradation)
Becomes brittle in freezing temperatures

Code: Approved by IPC and UPC for hot and cold water supply. Some jurisdictions restrict CPVC in certain applications.

Size it: Pipe Sizing Calculator →

PVC Pipe (Schedule 40)

Cold supply & DWVC=150 · Solvent welding (PVC cement)

140°F maximum — do not use for hot water, use CPVC instead

Advantages

Low cost compared to metal pipes
Lightweight and easy to install
Excellent chemical resistance
Smooth interior (C=150) for good flow

Limitations

Not suitable for hot water (use CPVC)
Becomes brittle in freezing temperatures
Requires proper support (sags more than metal)
UV degradation if exposed to sunlight

Code: Approved by IPC and UPC for DWV systems. Some jurisdictions restrict PVC for water supply — always verify local code.

Size it: DWV Pipe Sizing Calculator →

Black Iron Pipe (Schedule 40)

Fuel gas onlyC=100 · Threaded joints with gas-rated dope or tape

Not a water-service material; rated for fuel gas distribution

Advantages

Code-approved for gas applications
High strength and durability
Threaded connections (secure joints)
Suitable for high-pressure applications

Limitations

Requires corrosion protection
Heavier than plastic alternatives
Requires skilled installation (threading)
More expensive than plastic gas pipe

Code: Sizing must follow NFPA 54 (National Fuel Gas Code) capacity tables, which account for pipe size, length, pressure drop limit and gas type. All gas work requires permits.

Size it: Gas Line Sizing Calculator →

Code References & Best Practices:

IPC 2021 Table 605.4 — approved water distribution pipe materials; confirms copper, PEX and CPVC for supply and excludes PVC in many jurisdictions.
IPC 2021 Table 702.1 — approved DWV pipe materials, where Schedule 40 PVC is the default choice.
UPC 2021 Chapter 6 — water distribution material approvals; UPC and IPC differ on PVC for potable supply, so confirm which code your AHJ has adopted.
NFPA 54 (National Fuel Gas Code) — capacity tables governing black iron gas pipe sizing by length, pressure drop and gas type.
ASTM B88 — copper tube Types K, L and M; outside diameter equals nominal size plus 1/8".
ASTM D1785 — Schedule 40 PVC dimensions. ASTM F441 covers Schedule 40/80 CPVC.
ASTM F876 / F877 — PEX tubing and fittings, including the 160 PSI at 73°F / 100 PSI at 180°F pressure derating.

Looking for Dimensions?

This page compares materials. For outside diameter, inside diameter, gallons per foot and flow capacity at each nominal size, use the pipe size chart.

Pipe Size Chart →Schedule 40 Dimensions →Friction Loss Calculator →

Frequently Asked Questions

Which is better, copper or PEX?

They win on different things. Copper lasts 50–70+ years, handles 400°F and holds 200 PSI hot or cold, but costs the most and needs skilled soldering. PEX is smoother (C=150 vs 140), freeze-resistant, far cheaper and faster to run with fewer fittings — but derates to 100 PSI at 180°F, degrades in UV, and cannot be direct-buried unprotected. For a repipe inside conditioned space, PEX usually wins on cost. For exposed runs, mechanical rooms and anywhere UV or high temperature is in play, copper wins.

Can PVC be used for hot water?

No. Schedule 40 PVC is rated to 140°F maximum. Hot water supply requires CPVC, which is rated for 180°F continuous, or copper or PEX. Using PVC on a hot line will soften and eventually fail it.

What is the difference between PVC and CPVC?

Chlorination. CPVC is chlorinated PVC, which raises the temperature limit from 140°F to 180°F continuous and the pressure rating from 450 PSI to 400 PSI at 73°F while holding 100 PSI at 180°F. CPVC costs more, needs CPVC-specific cement, and is approved for hot and cold supply; standard PVC is a cold-supply and DWV material.

Which pipe material has the best flow rate?

PEX, CPVC and PVC all have a Hazen-Williams C-value of 150, making them smoother than copper at 140. Black iron is roughest at 100. The difference is small in short runs but compounds over long developed lengths, which is why C-value is an input to friction loss calculations.

What pipe is used for gas lines?

Black iron (Schedule 40) is the standard approved material for fuel gas distribution, joined with threaded fittings and gas-rated dope or tape. Sizing must follow NFPA 54 capacity tables, which account for pipe length, allowable pressure drop and whether the gas is natural or propane. Never substitute a water-service material on a gas line.

Is PEX approved by code?

Yes — PEX is approved by IPC, UPC and most local codes for water supply. Some jurisdictions restrict it in specific applications, so confirm with your AHJ before a repipe. The bigger code trap is PVC: IPC and UPC differ on whether it is acceptable for potable supply.

Why does black iron pipe have a low C-value?

Its interior surface is rougher than plastic or copper, giving a C-value of 100. For gas that matters less than for water — gas sizing uses NFPA 54 capacity tables expressed directly in BTU/hr rather than a friction coefficient.

Which pipe material is cheapest?

PVC on material cost, followed by PEX, then CPVC and black iron, with copper the most expensive. Material price is only part of it: PEX often beats cheaper materials on installed cost because its flexibility eliminates fittings and labour hours.