How Long Do Galvanized Pipes Last?
Originally, galvanized pipes were expected to have life expectancies of 50 to 70 years, or more. In real world usage however, many galvanized pipes started corroding in less than 25 years, and most after 40 years of service.
Galvanized steel pipes were commonly used from the early 1920's through to the 1960's. After the 1960's, piping made of copper or various types of plastic (PEX, CPVC, Polybutylene) became preferred materials over galvanized steel. This means that any galvanized plumbing still in a home, is almost certainly at least 60 years old: at or past its intended working life.
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What Is Galvanized Steel Plumbing?
Galvanization is the process of coating steel (or iron) pipes with a layer of zinc, protecting the steel from rust and corrosion.
Rust occurs when iron (a key element of steel) is combined with water and oxygen. As long as the zinc protective coating is intact, the underlying steel will not rust.
Zinc also combines with oxygen, to form zinc oxide. Unlike iron oxidation however, zinc oxidation occurs at a much slower rate. Nevertheless, all the zinc coating will eventually fully oxidize and wear off, exposing the underlying steel pipe to oxygen in water internally or air externally.
We provided some suggestions to help you identify galvanized plumbing in another article, in case you are unsure if you have galvanized plumbing.
Key Factors Affecting How Long Galvanized Pipes Last
Zinc quality and thickness: The thicker the zinc coating, the longer it will last before it fully oxidizes and wears away. There are also different methods for applying the zinc coating: some methods result in a lower percent of zinc in the coating, while others make it more likely that zinc can flake off in use or chip during installation.
Steel quality and thickness: once the steel in a plumbing system starts getting exposed to oxygen, the chemical composition of the steel, along with its thickness, will influence how quickly it rusts and corrodes.
Installation quality and methods: if an installation resulted in lots of nicks and abrasion to the protective zinc coating - steel around those weakened areas will start the rusting process much sooner. This is particularly true at fittings and connections.
Water pH level: Both the zinc protective coating, as well as the underlying steel, will oxidize faster in water that isn't pH neutral. Hard water tends to be more alkaline (high pH), and soft water tends to be more acidic (low pH). Hard water is also rich in minerals such as calcium and magnesium, which over time will cause scale build up - compounding pipe blockage and flow restriction problems from internal rust build up.
Hot vs Cold Water Lines: Hot water holds more oxygen in suspension. The higher oxygen levels, combined with the higher temperature, means the galvanized zinc layer and steel will corrode much faster on your hot vs cold water lines.
Pipes In Damp Areas: If galvanized pipes are located in damp areas such as underneath slab foundations, the outer zinc coating can degrade much faster. As the zinc coating degrades, the steel pipes will also rust and corrode due to the moisture levels, leading to possible breaks and leaks.
Once the steel in galvanized piping starts to rust, multiple problems will arise, getting progressively worse over time: drinking water may become discolored and taste rusty, internal rust and scale build up will restrict flow causing low water pressure at outlets, and thinning pipe walls can lead to leaks. You can read more about these issues in our article on the problems caused by galvanized pipes.
Get a Quote to Replace Your Galvanized Pipes
Here at Repipe Specialists, we've fully replaced the plumbing in over 75,000 homes since 1991 using both copper piping and PEX tubing. We continually get positive customer feedback from customers about their overall home repipe experiences. We often exceed their expectations on:
- Speed: Our repipe crews typically complete a repipe in a day, returning on another day for wall patching.
- Convenience: Through our One-Stop Repipe™ process, we handle everything from permits, to wall patching, to inspections.
- Cleanliness: Our crews are trained to protect your home while working (we cover all surfaces with protective sheeting), and to clean up fully at the end of each day.
- Peace of Mind: Repipe Specialists is a fully licensed plumber in every state we operate in, and we back all of our repipes with a lifetime warranty.
- Financing programs: To help take the sting out of unplanned repipe expenses, we offer several financing programs.
- Price: As a specialist that performs hundreds of repipes a week, we can deliver high-quality repipes at a lower cost vs generalist plumbers. We have an article that covers repipe cost factors in detail.
Schedule a free in-home consult, and one of our local repipe consultants will explain all your repipe options and provide you with a written, fixed-price quote.