Galvanized Piping – Defects

What is Galvanized Piping?

In this article, we are going to discuss defects commonly associated galvanized piping. In specific, internal galvanized pipe corrosion and how it affects the plumbing system. We will also discuss galvanized pipe remedies. First, however, lets understand the product and discuss the basic history of Galvanized plumbing systems. 

Galvanized piping is steel pipe that has been dipped in a protective zinc coating to prevent corrosion and rust. It was commonly installed in homes built between 1880 and 1960. When invented, it was an alternative to lead piping for water supply lines. Today, however, we have learned that decades of exposure to water causes problems. In particular, corrosion and rust on the inside.

As previously mentioned, galvanized pipes are dipped in molten, naturally occurring zinc. The naturally occurring zinc used is impure, meaning these pipes were bathed in zinc that also contained lead and other impurities. The zinc coating elongated the life of the steel pipes, but added small amount of lead and other substances that could potentially harm occupants.

When first installed, galvanized pipe looks similar to a nickel color. However, as it ages, the piping may appear much duller, lighter, or darker, depending on its environment.

New Galvanized Piping
Galvanized Pipe

Galvanized Pipe Corrosion - Can I tell?

Galvanized steel will corrode from the inside over time, making it almost impossible to tell just by looking at the pipes from the outside. The pipes rust away from the inside out, causing weak structural properties resulting in eventual leaks and collapses. They will also develop calcium deposits inside of the pipe. The resulting galvanized pipe corrosion can eventually clog the complete diameter with calcium build-up resulting in low water pressure and rusty colored water.

Watch for these tell-tale signs to spot issues before the galvanized steel pipes begin to leak or even rupture:

  • Rust around your pipe joints and pitted rust spots on your pipes.
  • Brownish water coming out of your faucets – Rust can end up in the water itself. This will be obvious if the water appears brownish or rust-colored after it has been left off for a long period. This is due to the water sitting in the pipe long enough to accumulate enough rust to make itself visible to the naked eye.
  • Yellow tinting to the water supply. This may be indicating that the piping is beginning to dezinc and lose its protective principles. 
  • Lower-than-usual water pressure. As the pipe’s internal diameter becomes narrower due to calcium build-up, the water has a much smaller path to traverse. This restricted flow reveals itself as lowered water pressure since there is simply not enough water making it through to provide the water pressure you need.
Galvanized Piping Corrosion
Galvanized Piping Corrosion


Typically, galvanized piping remedies are performed when leaks occur, or when to the needed frequency of repairs is great enough that replacement is warranted.  Proper repair can be costly and invasive, requiring removal of wall and ceiling coverings to access the pipe where it passes through the structure of a building.  Repair methods include epoxy lining the pipe, or replacing it with an acceptable replacement such as PEX, Copper, or CPVC.  Currently PEX is the common material used as it is flexible and cost effective.

A full replacement of the system is considered the proper fix. The cost to replace galvanized steel plumbing in the average house ranges between $1,500 and $15,000.

If your pipes are nuisance that require constant patching and repair, don’t prolong their suffering. If they’re made of lead (poisonous) or polybutylene (very high rates of failure and degeneration) they should have already been replaced. In general, galvanized steel pipes last 20-50 years, brass lasts 40-70, copper lasts over 50, cast iron lasts 75-100, and PVC can last over a 100 years if it’s not exposed to direct sunlight. Use these numbers as benchmarks when assessing if your pipes need replacement, but as always, get a second opinion from an expert before embarking on a full home re-plumbing.


Trust the certified professionals at Absolute Inspection Services to perform your home inspection! Contact us today at (888) HME-INSP [463-4677]!



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