Galvanized Water Lines: Rust, Low Pressure and Replacement

Why galvanized pipe fails the way it does

Galvanized steel is ordinary steel pipe with a zinc coating meant to slow rust. Over decades that coating wears away from the inside surface. Once bare steel meets water, rust and mineral scale build up on the pipe wall, and the opening the water flows through gets smaller and rougher.

That is why galvanized lines tend to fail slowly and then suddenly. First the pressure fades and the water may run brown after it sits overnight. Later the pipe wall thins at a threaded joint or a low spot, and a leak opens. Because the whole run has aged the same way, fixing one leak often just moves the next failure a few feet along.

How to tell if your service line may be galvanized

The pipe rising out of the ground at the house shutoff is dull gray, not reddish copper or plastic
Fittings are threaded rather than soldered or crimped
A magnet sticks firmly to the pipe (steel is magnetic; copper is not)
The house was built in the 1950s, 60s or early 70s and the line has never been replaced
Interior pipes visible in the garage or under sinks are also gray threaded pipe

Spot repair or full replacement for galvanized pipe

Spot repair

Fixes the one leak that has surfaced
Smaller dig and shorter shutoff
Leaves the rest of the narrowed, corroded pipe in place
Repairs at threaded joints can stress neighboring sections

Full replacement

New pipe from the meter connection to the house
Restores the full opening, which can improve pressure
Often paired with a new main shutoff valve
Larger project that may need a permit and inspection

Is it time to replace?

IfThis is the first leak and pressure is otherwise fineThenA repair may be reasonable, but ask how the rest of the pipe looks where it is exposed.
IfYou have had two or more leaks on the lineThenReplacement usually makes more sense than another patch.
IfPressure is weak at every fixture and water discolors after sittingThenThe pipe may be badly narrowed; replacement is worth pricing even before it leaks.
IfYou are also planning to repipe the houseThenDiscuss doing both so the new service line and interior pipes are sized and connected together.

Questions to ask a plumber about a galvanized line

Have you confirmed the material at the meter end and the house end?
What material and size would you use for the new line, and why?
Will the interior galvanized pipes limit the improvement in pressure?
Will you install a new main shutoff at the house?
Who handles any permit and inspection with the city?

Common questions

Is rusty water from galvanized pipe dangerous?

Discolored water is a sign of corrosion and a reason to have the piping evaluated. If you have concerns about water quality, ask the City of Fullerton's water utility and consider having your water tested.

Will a new service line fix low pressure if the house is still galvanized inside?

It can help, but narrowed interior pipes may still limit flow at fixtures. A plumber can test pressure at the meter side and inside to show where the restriction is.

Can galvanized pipe be cleaned out instead of replaced?

Scale and rust in galvanized pipe are part of the corroded wall itself. Replacement is the usual fix for a service line in that condition.

General information for Fullerton, not a quote or professional advice. In an emergency, call 911.