What should I look for when buying supply pipe materials: copper vs pex vs cpvc?

PEX is the best choice for most DIY repiping projects -- flexible, forgiving, and affordable. Copper is worth the premium if longevity and resale value matter most. Use push-fit fittings to transition between pipe types during repairs.

What are common mistakes when buying supply pipe materials: copper vs pex vs cpvc?

Using PVC (white) for hot water supply. PVC is for drains only. CPVC (cream) is the hot-rated version. Exposing PEX to sunlight. Even indirect UV degrades it. Cover all exposed runs. Mixing PEX types without the right fittings. PEX-A expansion fittings do not work on PEX-B.

Supply Pipe Materials: Copper vs PEX vs CPVC

Overview

Copper, PEX, and CPVC are the three materials used for residential water supply lines. Each has strengths and tradeoffs in cost, durability, installation difficulty, and longevity. PEX has largely replaced copper in new construction due to lower cost and easier installation, but copper remains the premium choice.

What to Know

Copper

The proven standard for 70+ years. Type M for residential supply. Soldered or push-fit connections. Bacteriostatic, handles UV, fully recyclable. 50+ year lifespan. Drawback: expensive, requires soldering skill or push-fit fittings. $2-4 per linear foot for pipe, plus fittings.

PEX

Flexible cross-linked polyethylene. Red for hot, blue for cold. Freeze-resistant, corrosion-proof, runs in long lengths with fewer fittings. Crimp, expansion, or push-fit connections. Cannot be used outdoors (UV degrades it). 25-50 year expected lifespan. $0.50-1.50 per linear foot.

CPVC

Chlorinated PVC rated for hot water supply up to 200 degrees F. Cream/tan colored. Solvent cement connections (permanent). Cheapest material but joints are rigid and can be brittle. 25-40 year lifespan. $0.50-1.00 per linear foot. Some areas restrict CPVC by code.

Comparison

Copper: $$$, 50+ year lifespan, soldering skill needed, premium choice

PEX: $$, 25-50 year lifespan, easiest installation, most popular for new construction

CPVC: $, 25-40 year lifespan, solvent cement joints, cheapest but becoming less common

Buying Tips

PEX is the best choice for most DIY repiping projects -- flexible, forgiving, and affordable.
Copper is worth the premium if longevity and resale value matter most.
Use push-fit fittings to transition between pipe types during repairs.
Check local code -- some areas restrict CPVC or require specific PEX connection methods.

Common Mistakes

Using PVC (white) for hot water supply. PVC is for drains only. CPVC (cream) is the hot-rated version.
Exposing PEX to sunlight. Even indirect UV degrades it. Cover all exposed runs.
Mixing PEX types without the right fittings. PEX-A expansion fittings do not work on PEX-B.
Using copper in aggressive water (low pH) without testing. Acidic water corrodes copper rapidly.

Bottom Line

PEX is the best value for most residential projects. Copper is the premium, long-term choice. CPVC is the budget option but is declining in popularity. Check local code before choosing.