Walk your basement with a flashlight and you'll likely find three or four different pipe materials, each a fossil of its installation era. When repairs and repipes come up, the material question follows — and the answer isn't brand loyalty, it's fit. Here's the working guide to what goes where, and why your plumber reaches for what they reach for.
PEX: the modern default for supply
Cross-linked polyethylene — the flexible tubing in red, blue, and white — now dominates supply-line work for good reasons: it snakes through structure with few fittings (fewer joints, fewer leak points), tolerates minor freezing better than rigid pipe by flexing, installs fast, and resists the water-chemistry corrosion eating older metal systems. Its limits: UV sensitivity (never outdoors exposed), it can't connect directly to a water heater (a short metal transition handles that), and rodents will occasionally chew it in accessible runs. For repipes of failing galvanized, PEX is usually the value answer.
Copper: the proven veteran
Copper remains excellent — durable, heat-tolerant, UV-proof, rodent-proof, and time-tested over seventy years. It costs more in material and labor (rigid runs, soldered or pressed joints), and in some water chemistries it develops the pinhole leaks familiar across parts of New Jersey. Where copper still gets specified: exposed runs (mechanical rooms, outdoor-adjacent), water heater connections, and homes where the owner values its track record and the budget allows. Repairing existing copper with copper is routine; transitioning copper to PEX mid-system is equally routine with the right fittings.
PVC and CPVC: drainage and the hot-water asterisk
White PVC owns drainage: waste lines, vents, sewer laterals — smooth-walled, corrosion-proof, joints solvent-welded into effectively one piece. It is not rated for hot supply water or pressure at temperature. CPVC (the cream-colored cousin) is rated for hot and cold supply and had its era; it grows brittle with age, and cracked CPVC repairs are now a familiar service call. We repair CPVC systems readily but rarely recommend expanding them — a failing CPVC section is usually a PEX transition opportunity.
Reading your own basement
Gray threaded metal: galvanized steel supply — the aging system whose failures come in clusters. Reddish metal: copper. Black heavy pipe with hub joints: cast-iron drainage. White plastic: PVC drainage. Cream plastic on supply: CPVC. Flexible colored tubing: PEX. Mixed systems are normal — homes accrete plumbing in layers — but every metal-to-metal transition (galvanized to copper especially) should have a dielectric fitting preventing galvanic corrosion, and often doesn't. Lumin Drain NJ repairs and repipes in all of the above across New Jersey, matching material to the job rather than the trend: 929-662-1816.