What galvanized pipe is
Galvanized pipe is steel coated with zinc to slow rusting. It was the standard for water lines in many American homes until the mid-1900s, including much of Los Angeles. The zinc wears away over the decades, and the steel underneath starts to rust from the inside.
How to tell if you have it
Look at the pipes near your water heater, under sinks, or where the main line enters the house.
- Color: galvanized pipe is dull gray or silver. Copper is orange-brown, or green with age.
- Fittings: galvanized pipe uses threaded fittings that screw together.
- Magnet test: a magnet sticks firmly to galvanized steel and won’t stick to copper.
- Scratch test: scratching galvanized pipe shows silver-gray metal, while copper shows a bright penny color.
Problems galvanized pipes cause
- Low water pressure, as rust narrows the inside of the pipe.
- Brown or rusty water, especially in the morning.
- Leaks at threaded joints and pinholes in the pipe.
- Uneven pressure, where some fixtures work fine and others barely trickle.
In some older homes, galvanized pipe can also collect lead from older plumbing upstream, which is one more reason to replace it.
Repair or repipe?
If you have one leak in an otherwise healthy system, a repair is fine. But galvanized pipe ages all at once. If you’re seeing low pressure throughout the house, rusty water or leaks in more than one spot, the rest of the system is likely close behind, and repiping usually costs less than years of repairs.
What repiping involves
A repipe replaces all the water supply lines with new copper or PEX. Most single-family homes take a few days. Small openings in walls and ceilings let the new lines through, and the work is pressure-tested and inspected before those openings are closed. Many homeowners stay in the house the whole time.
Don’t forget the main water line
If your house has galvanized pipe inside, the line from the meter to the house may be galvanized too. Replacing it at the same time often makes the biggest difference to water pressure.