If your home predates about 1960 and hasn’t been repiped, there’s a fair chance the water supply lines are galvanized steel. It’s worth knowing, because galvanized has a defined lifespan and a lot of these systems are past it.
The two-minute identification test
Find an exposed section — at the water heater, under a sink, or where the line enters the house — and check two things.
Magnet: it sticks to galvanized steel. It won’t stick to copper or plastic.
Scratch it with a screwdriver. Silver-grey underneath with threaded fittings means galvanized. Reddish-brown underneath with soldered joints means copper. White, cream or blue plastic is PVC, CPVC or PEX.
Why it fails
Galvanized pipe is steel coated in zinc. The zinc protects the steel, but it erodes from the inside over decades, and once it’s gone the steel rusts. Crucially, that rust builds inward rather than falling away — the bore narrows progressively. Cut open an old galvanized line and the opening can be down to the width of a pencil.
Expect 40 to 60 years. A home from the 1950s with original supply lines is well past due.
Signs yours is finished
- Brown or rust-tinted water, particularly on first use in the morning.
- Water pressure that has faded gradually over years — so gradually you stopped noticing.
- One fixture much weaker than the rest, usually the one furthest along the run.
- Visible rust or bulging at threaded joints.
- Pinhole leaks appearing more often than they used to.
Copper isn’t forever either
Copper is a major upgrade but it has its own life, typically 50 to 70 years depending on water chemistry and workmanship. It fails through pinhole corrosion — tiny perforations that tend to appear in clusters once the wall has thinned.
The diagnostic: one pinhole leak is bad luck. Three in a year is the system telling you it’s done, and continuing to patch it is money spent on a pipe that will fail again somewhere else.
Repair or repipe
Patch when the pipe is otherwise sound and this is a first failure. Repipe when you’re seeing rusty water, repeated leaks, or system-wide pressure loss — or when walls are already open for a renovation, which is when the marginal cost is lowest.
A repipe takes most homes two to four days. Ask whether drywall repair and paint are in the quote, because that’s the line item most often left out and it’s not trivial.
We handle repipes and pressurised line work here — see our pipe repair services. In Southern California, where post-war housing and hard water make this especially common, repiping specialists in San Dimas cover the same work across the San Gabriel Valley.
Before you decide
Establish the material and the age of your supply system, and make the decision on that basis rather than one leak at a time. Homeowners who repipe reactively almost always spend more than those who plan it.
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