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

Friday, June 15, 2018

Cast iron pipe is recognizable by its black finish and the bulge at the end of each pipe section, called a “hub,” that the adjacent pipe fits into. Surface rust may eliminate the black finish on extremely old cast iron, leaving it simply rust-color. It was installed for new construction up until the late-1960s for drain pipe only and is still available, but only used for repairs.

    It is approved for drain/waste/vent, not pressurized water supply, and cast iron is mostly concealed in older homes where it is still in use. The places it might be visible are at the laundry as a the standpipe behind the washing machine, in the attic as a vent pipe through the roof, and as exposed drain pipe from plumbing fixtures above it in the crawl space under a home with elevated wood floors.

    Corrosion eventually eats completely through the pipe, allowing sewage to drip out. Although the rust-through is at the back of a vertical pipe in the photo below, it occurs more often at the bottom of horizontal pipes in a home’s crawl space.

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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? 

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 is a galvanized nipple?

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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