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What is the difference between cast iron and black pipes?

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In properties, your piping is one of the most important parts of your plumbing. You have water pipes, sewer pipes and gas pipes that all contribute to the safe and efficient travel of water and gas throughout your commercial or residential property.

What is the difference between cast iron and black pipes? Photo

Your pipes are something that you may not know about because they are hidden underground or inside your walls. In this blog, we can shed some light on what kind of piping is used. This can help you with future repairs, replacements and potential leaking or burst pipes.

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Cast Iron Pipe

Cast iron pipes have been used for many years and are very durable for gas lines and water. It is pure iron and although their life expectancy is between 80-100 years, they can fail due to corrosion and cracks. They were used for many centuries because they were a relatively cheap product for water lines at the time.

Cast Iron pipes are super quiet due to their thick density and are fire-resistant and do not give off gasses that are harmful and potentially deadly.

Black Iron Pipe

Black iron pipe or ABS is made from acrylonitrile butadiene styrene and is commonly used for drain, waste and vent pipes. It is similar to PVC pipes in size and functionality.

It is highly durable and known for its corrosion resistance. Black pipes are light and easily malleable.

It is easy to cut and assemble and is lightweight due to its low density. They can be noisy however when water travels through at high speed and pressure.

Main Differences Between Cast Iron and Black Pipes


When working with Cast Iron or Black Pipes, there is a difference between the process of installation. With cast iron, were traditionally sealed with melted lead and oakum.

But nowadays, stainless steel bands and rubber gaskets are used. A black pipe is connected with ABS cement and couplings.


Black pipes come in 8 feet in length and their diameter size ranges from 1 1/2 to 4 inches. The diameter size depends on the fixtures connected to the pipe.

They come in pieces and can be clipped together. Cast iron pipes come in diameters of 2 inches and up and 4-6 inches for residential drains.


There is a major difference when it comes to repairing these pipes if they leak. Because Black steel pipes are separated into pieces, the risk of leaks and water escaping from the joins is greater.

Cast iron pipes are welded at the join so the chance of leaks is less but corrosion can still occur over time. When ABS or steel pipe fails, replacement of the damaged section is the ideal solution however it can be difficult to rectify.

Overall Use

6 Types of Pipes Used in Building Construction

Both cast Iron and black pipes are routinely used for water lines and gas in residential properties. Black pipes are durable and are mainly used for gas lines, and for major water channels, cast iron is preferred.

The cost to install is all down to materials and installation method. Cast iron is usually more costly due to the size and process of installation.

Initial set-up is pricey but it will save you money, energy and resources in the long run.

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