Black Iron Pipe vs Steel Pipe

A wrench tightened around a length of black iron pipe.

The piping in your home is not something you see very often. Unless you have run some of your own lines or conducted your own plumbing repairs, you might not see it at all. However, understanding what kinds of piping might be in use in your home could be helpful in the event that future repairs need to be performed.

Steel Pipe

Steel pipe comes under many different names depending on what it looks like and exactly how it’s been made. It’s a durable material that doesn’t corrode very easily, so it can serve as functional piping for many applications.

Black Iron Pipe

This type of piping used to exist more commonly in houses built before the 1960s. It is actually a form of steel pipe, but it’s made with a slightly different composition of materials to make it a little more malleable. However, water does corrode this type of pipe fairly easily in comparison to steel.


Steel and black iron pipe both used to be common for water lines in homes, but they’ve fallen out of use in favor of plastic PVC instead. Black iron is mostly used strictly for gas lines because of its durability, while steel is often reserved for major water lines such as those leading from a main to your home or those in your septic system.

Some Major Differences

The main difference you’ll have to worry about with these two materials is their construction. Black iron comes in pieces and so runs of these pieces will have seams with connectors fastening them together. On the other hand, steel pipes are usually welded. Both can be hard to work with, especially in comparison to PVC, even for the pros.

This variation in construction leads to differences in repair methods as well. On the whole, leaks in runs of black iron pipe are much harder to repair, as their connections are the likely places for a leak. Since steel has welded joints instead, they’re far less likely to leak to begin with, and easier to fix when they do.

Both of these piping types usually cost more than PVC, which is part of the reason it’s so prevalent in construction, but steel actually trumps black iron for initial cost. The piping itself runs about 20 percent more expensive than black iron, although it saves energy and resources in the long run.