If you’re buying a home built before 1970, there’s a good chance your drain waste system is made of cast iron. 

Opinions vary about the functionality and durability of cast iron. You’ll have to separate fact from fiction, shut out the noise, and make a smart decision about your future or existing home.

Cast iron plumbing has been in use for hundreds of years because it’s so durable, and because it also does a great job of insulating noisy running water. So why the bad rap? It’s all in the chemistry.

Potential Dangers of Cast Iron Piping

When cast iron pipes carry waste hydrogen sulfide gasses are created. When these gasses oxidize, corrosive sulfuric acid is created, rusting the pipes from the inside out. 

The rust flakes within the pipe can gather in one location and restrict the flow of water: slow drainage is often the first indication of a problem, and homeowners may find themselves calling the plumber every six months to clear out the pipe.

If the pipes are located below the slab, inspecting them will be difficult. Hire an experienced, licensed plumber for an Austin home inspection to insert a Borescope into the drain to view the interior of the pipe.

How To Replace Your Cast Iron Pipes

If the home is built on piers and beams, spot repairs can be tempting. Why not just replace the few feet of pipe where the problem is? This isn’t recommended.

It’s difficult to get a licensed professional to warranty their work unless all of the antiquated pipes are replaced. Spot repairs to the pipes can expose the foundation system (if they leak again) to excessive, undetected moisture which could cause unwanted settlement and mold. If you notice there have been previous spot repairs or possible leaks, calling out mold inspectors is also recommended. 

So keep cast iron piping or cast it out? Older cast iron waste pipes should be judged on a case-by-case basis. First hire an experienced home inspector to collect information about the drain waste system’s performance. 

Ask your home inspector to do a visual inspection of the pipes if possible. If the person performing your property inspection is any good at all he to she will flood test several sinks and tubs to identify slow drainage.

But slow drainage can be related to other problems and may not indicate damaged cast iron pipes, so your second step is to hire a licensed professional plumber to evaluate the interior and when possible the exterior of the pipes.

Failure to replace or line the damaged pipes may result in more headaches down the line.

Know the facts, know your home, and know your options. If you’re not sure what sort of pipes your home (or potential home) has, get a thorough home inspection to find out. 

And don’t get it checked, get it double-checked!