How To Look At A House

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When should I replace my galvanized steel pipes?

Tuesday, February 4, 2020

The average lifespan of galvanized steel water supply pipe is 40 to 60 years. Galvanized pipe was gradually phased out of new construction during the 1960s and not used at all for new homes by the mid-1970s. So any galvanized pipe still in place is at, or very near, the end of its serviceable lifespan.

    Corrosion is the culprit that shortens its serviceable life, and the pipe literally rusts from the inside out. Loose rust particles collect behind faucets and reduce water flow at fixtures over time, causing a plumbing version of arteriosclerosis, as shown in the photo below of the end of an abandoned galvanized steel pipe that has been cut off behind a washing machine faucet. 

    If your galvanized steel pipes are over 40 years old, here’s several ways to tell when it's time to change them out:

•• Low water flow at faucets - The rust particles that collect behind the faucets in your home over time will cause what seems like low pressure at the sinks and tub spouts, especially when you first turn the water on.

•• Pressure differences between fixtures - You might find, for example, that the bathroom sink is fine, but water flow at the bathtub is low. Alternately, a common sympton is that the flow at the bathroom sink drops to a trickle when the bathtub is being filled.

•• Rust discoloration of water - You will notice this when you first turn a faucet on that hasn’t been used for several days. There will also be occasional rust flakes in a glass of water.

•• Leaks - A problem called “galvanic corrosion” occurs with galvanized pipe any time there is copper nearby in the system, such as at a water heater. It’s a crumbly cancerous growth that eventually causes leaks.  To learn more about it, go to our blog post What's that powdery crust on the pipe connections at the water heater? Ordinary rust can also progress far enough to cause leaks. The place to look is at shut-off valves under sinks, at toilets, and above the water heater, especially at the wall penetration. Here’s a few examples below of both rust and galvanic corrosion. 

    If you are not sure if your pipes are galvanized steel, see our blog post How can I tell what type of plumbing pipe I have?

    It is possible, however, that although you see galvanized steel pipe coming out of the wall at your plumbing fixture, you may have copper piping with galvanized nipples. An example is shown below at a wall where a galvanized steel nipple in a copper pipe system was recently replaced, but the wall opening was not repaired yet. To read more about it, go to What is a galvanized nipple?

    If you see any of the above symptomes, a plumber can advise you about how urgent it is to replace your pipes. There are multiple choices for replacement pipes, but the most popular today are CPVC and PEX. 

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Here’s links to a collection of our other blog posts about PLUMBING PIPES:

How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

Can galvanized steel pipe still be used for new water lines in a house? 

How can I tell if I have cast iron pipes in my house? 

Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

What is the difference between green and white sewer drain pipes?

Is a washing machine drain hose required to be secured at the standpipe?

What are the abandoned pipes sticking out of the wall in my house?  

What are the code requirements for plumbing vent terminations?

What are the code requirements for layout of drain piping under sinks?

What causes a gurgling sound when a bathtub or sink drains? 

What is a "combination waste and vent" in a plumbing system? 

What is a building trap?  

What are the pipes sticking out near my water valves?

How do you accurately find a broken water pipe leak under the floor slab?

What is the difference between water pipe and sewage (waste) pipe? 

Are plastic pipes (PVC, CPVC, and PEX) safe for drinking water? 

Is a hot water faucet handle required to be on the left? 

What is a dielectric union? 

What's that powdery crust on the pipe connections at the water heater? 

If all the plumbing drains have water in them and you can still smell sewer gas, what's causing the problem?  

How can I tell what type of plumbing pipe I have?

Why is there a flexible accordion pipe under the sink? 

What is the difference between PVC and ABS plumbing pipe?

What is the difference between water service pipe and water supply pipe? 

What are the pipes on my roof? 

• How can I find out what type of water pipe runs underground from the water meter to the house (service pipe)?

What is a P-trap?

Why is old galvanized steel water pipe a problem for homebuyers?

What does polybutylene pipe look like? Why is it a problem? 

• Which water pipes are an insurance problem and possibly uninsurable?

• Can you connect CPVC pipe directly to a gas water heater?  

     Visit our PLUMBING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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