Plenty of Portland homes still have their original galvanized steel water lines. They often work fine for decades — until they don't, and the failure tends to come all at once.
Galvanized pipe is steel coated in zinc to slow rust. It was a standard material for household water supply lines through much of the twentieth century, which is why it turns up so often in Portland's older bungalows, foursquares and mid-century homes — sometimes alongside newer copper or PEX where a previous owner replaced part of the system.
To check, look where the water line comes into the house and where pipes connect to the water heater. Galvanized pipe is dull gray, joined with threaded fittings, and a magnet will stick to it. Copper is reddish-brown and a magnet won't stick. PEX is flexible plastic, usually red, blue or white.
Over decades, the zinc coating wears away and the steel underneath corrodes. The rust doesn't just thin the pipe wall; it builds up inside, narrowing the opening the way plaque narrows an artery. A pipe that looks solid from the outside can be mostly closed off inside.
The threaded joints are the weakest points. Cutting threads into the pipe removes metal, so the wall is thinnest exactly where the fittings are — and that's where leaks and breaks usually start.
This is the part that catches people off guard. Old galvanized lines that are badly corroded can be stable as long as nobody disturbs them — and then snap at a fitting the moment someone bumps them while replacing a water heater, swapping a faucet or working in a crawl space. It's a common story from plumbers working in older homes: a routine job turns into an emergency when a corroded elbow gives way.
If you're planning work that will involve the water lines, it's worth knowing ahead of time what you have. And if one does break, close the main shutoff right away — our guide to first steps after a burst pipe covers what to do next.
When a single section leaks, replacing just that section is a reasonable short-term repair. The trouble is that the rest of the system is the same age and in similar condition, so one repair often leads to the next. And connecting new pipe to old galvanized pipe disturbs the old pipe, which is exactly how breaks happen.
Replacing the galvanized supply lines throughout the house with PEX or copper restores full pressure and ends the cycle of leaks. What it involves depends on how the house is built: how accessible the lines are from a basement or crawl space, how many fixtures and floors there are, and how much wall or ceiling has to be opened to reach them. The pipe repair and water line repair pages explain how we approach each.
The pipe from the meter to the house can also be galvanized, even if the interior plumbing has been updated. If pressure is low everywhere in the house, including at fixtures on newer pipe, the service line is a likely suspect.
If you have questions about what's in your tap water in an older house, testing is the way to find out. The Portland Water Bureau has offered lead-in-water testing to its customers — check the bureau's current program for details.
Low pressure, rusty water, or a leaking joint on old pipes? Call us at (971) 386-1515 — we're available 24/7.