What are Galvanized Pipes?
Galvanized pipes are steel pipes coated with zinc to prevent rusting. This is a common process still used today to make steel last longer when exposed to moisture. They used threaded connections. Galvanized steel pipes for home plumbing fell out of use in the late 1950's.
How Long do They Last?
Galvanized pipes last around 40-50 years. Since galvanized plumbing wasn't used past 1960, any galvanized pipes in use today have surpassed their expected service life, and should be replaced.
Why do They Leak?
Despite the zinc coating, galvanized steel pipes still rust over time. The pipes tend to rust from the inside out. Since rust expands up to 10x the original size of the metal as it forms, the inside of the pipe can become constricted or clogged. The thin areas where metal has turned to rust (or where the pipes are threaded) are highly vulnerable to cracking and leaking.
Do I Have Galvanized Pipes?
If your home was built before 1960, you may have galvanized pipes, or sections of galvanized pipe in your home. As homes are renovated and updated throughout the years, readily accessible sections of pipe may be upgraded, while inaccessible runs of pipe (inside walls, etc.) are left alone. Galvanized pipes are a dull silver color, use threaded connections, and are magnetic.
If you don't see any exposed galvanized pipes, but experience lower than normal water pressure, or brownish coloring in the water, failing galvanized pipes may be the culprit.
What Can I Do?
The best way to deal with galvanized plumbing is to replace it. Since any galvanized pipes still in use will be well past their expected service life, it is only a matter of time before a leak develops. Galvanized pipes can be an insurance issue for this reason. We recommend talking with your insurance company to ensure that you can obtain plumbing leak coverage for your system.
Consult a plumber about the scope and cost of replacing your system, or about further investigation if you suspect you may have galvanized pipes.
Key Points
Galvanized pipes are steel treated with a rust-inhibiting layer.
They were used until the late 1950's.
Any pipes still in use are past their expected lifespan.
They rust from the inside out.
Talk to your insurance company if you have them.
Consult a plumber about having them replaced.