Cast iron toilet drain

53 year old cast iron toilet drain and stack. No signs of actual leaks. Possible mineral deposits on exterior and significant surface rust. (the white puffy stuff at the top is spider webs)

I’d like to call this out but don’t want to be an alarmist. Any insight from you more experienced fellows?

Assuming your observations are correct, there is nothing to call out. But, that is not to say that you should not identify that these components are made of cast iron, and the inherant concerns with 50 year old cast iron, because you should.

Surface rust is not a concern. May be caused by a leaking flange. Just make sure you check the subfloor for damage.

Thank you kindly for your reply, Jeffrey.

Inform them the visible DWV system is Cast Iron.

If you can locate the cleanouts tell them where they are.

Recommend that the system be Video Scanned by a Plumber.

There is a town is south suburbs of Chicago that requires cast iron as drain material,even in new construction. They tried changing it years ago, it didn’t pass.
Just like Jeff stated, age is the concern as well as obvious leaks.

A good quality cast iron pipe, installed under proper conditions, has a life expectancy of 75 – 100 years, and possibly even more. Cast iron does rust but when it does the rust actually forms a barrier layer over the remainder of the pipe which helps protect it from further rusting.

Still used today for vertical and horizontal installations for roof leaders and waste pipes because they are less noisy in commercial and residential with multiple levels.

Unless they are showing subject to extreme rusting and leaking, I would only comment to the fact that the waste drainage is cast iron along with the location of clean-outs as mentioned.

When I know of cast iron I recommend a sewer scope
Most times it does come back with issues

I agree that scoping would be prudent after 50 years.

…Especially considering that most “rust-out” occurs from the inside out, so you won’t necessarily know of an issue until it breaks through.


For those interested in the History of the cast iron pipe.

Clogged arteries from 1964

Thank you gents. They already scoped the sewer but from the exterior cleanout to the street. I’m going to mention the life expectancy of cast iron and galvanized drain pipe to cover my butt.

I did find a galvanized drain which is rusting through the bottom. That one is definitely gonna be called out. I hope they find a skinny plumber to “crawl” all the way to the other side of the crawlspace!

Galvanized is a different animal and has a TLE of 40-60 yrs. and is almost always fully depreciated in that span.

Very Helpful gentleman!

Cast iron is used in new construction all the time and I see it in 200 year old buildings that there is no problem with. When I find problems it looks like rusting through and split pipes.

No visible, exterior problems, that is :wink:

Well sure, that’s pretty obvious, no? How many years and/or quality of water do you think it takes to get to that point?
The pipe could “look fine” and still be at the threshold of failure - in between the two scenarios you described.
A visual home inspection has really no way of accurately assessing here (unless obvious things are visible, like in your pics), without a sewer scope. The prudent thing to do is always highly recommending/stressing that professional sewer scope to your clients and educating them on cast iron and the potential ramifications of issues that can arise with older sewer piping.
One other thing, I’m always surprised at the # of people who don’t realize the sewer pipe from the house to the street is their responsibility. They think that the house has new PVC drains, up to the foundation penetration, and they’re good to go :wink:

whooops, didn’t realize that this was a phantom thread from last year :neutral:
and other replies basically stated the same thing I did :slight_smile:

I just say, 'corrosion observed but no leaking visible". That way I’m covered if it fails.