Understanding Different Pipe Materials in Your Home

Copper Pipes

Copper is the gold standard for residential water supply lines and has been used for decades due to its durability, resistance to corrosion, and reliability. Copper pipes are identified by their distinctive reddish color and smooth surface. They come in rigid lengths (type M, L, and K, with K being the thickest) and flexible rolls for tight spaces. Copper's main drawbacks are cost, susceptibility to pinhole corrosion in aggressive water, and the skill required for soldering connections. Copper pipes typically last 50 to 70 years.

PEX Tubing

PEX (cross-linked polyethylene) has become the most popular choice for residential water supply in new construction. It is flexible, inexpensive, freeze-resistant, and easy to install using crimp, clamp, or push-fit connections — no soldering required. PEX comes in red (hot water), blue (cold water), and white (either) for easy identification. It can be snaked through walls like electrical wire, reducing the number of fittings needed. PEX cannot be used outdoors (UV sensitivity) and has a shorter track record than copper, though it is expected to last 40 to 50 years.

PVC and CPVC

PVC (white) is used exclusively for drain, waste, and vent lines — it cannot handle hot water or pressure supply applications. CPVC (cream or light yellow) is a temperature-rated variation that can be used for hot and cold water supply lines. Both are lightweight, inexpensive, and joined with solvent cement. PVC is rated for temperatures up to 140°F, while CPVC handles up to 200°F. These materials are prone to cracking from impact and should be protected in exposed locations.

Galvanized Steel and Cast Iron

Galvanized steel pipes (dull gray, magnetic) were common in homes built before 1960. They corrode internally over time, restricting flow and discoloring water. If your home has galvanized supply pipes, plan for replacement with copper or PEX — most galvanized pipes have exceeded their 40- to 50-year lifespan. Cast iron pipes (heavy, dark gray to black) were used for drain and sewer lines in older homes. While durable, they eventually rust and deteriorate. Both materials can be replaced section by section using transition fittings that connect old pipes to modern materials.