Rust on outside of cast iron sewer pipe


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Old 04-30-18, 08:48 AM
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Rust on outside of cast iron sewer pipe

Hi all

I was working in my laundry room and notices my main sewer stack has what appears to be corrosion. The pipe (cast iron) has been painted at some point, and this doesnt quite look like it was a 'missed' spot, although it would have been tougher to reach for the painter.

I am wondering if this is 'a big deal' and needs immediate attention, or if this is a 'its old cast iron, replace it next time you have major plumbing work done' sort of thing...

Here is the pic:
 
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Old 04-30-18, 09:00 AM
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I would wipe it off as best you can and keep an eye on it to see if anything is leaking out.
 
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Old 04-30-18, 09:16 AM
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Is it up against a cold exterior wall that might become the coldest spot in the Laundry Room and condense the moisture that's often carried in the air there ?

The spot doesn't quite have the red look of rust ?
 
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Old 04-30-18, 09:32 AM
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I am worried it might be a sewer leak. This is a split level home-- that part of the wall is actually facing the top of the basement wall on the other side.

Any tips on what to use to clean it, I am worried going after it with a metal brush might be too harsh

I have sewer line an 'in home plumbing' protection program through the water company. Wonder if I should call them-- I wanted to have a sense that is might be an actual problem before engaging them...

Thanks for taking the time to reply!
 
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Old 04-30-18, 11:03 AM
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It's cast iron. You really can't be too "harsh". A wire brush, putty knife or just wipe the area off with a cloth. You want to get it clean enough that you are able to notice any leakage.
 
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Old 04-30-18, 03:49 PM
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I have several of those "rusty" areas too. I've just wire brushed and sanded them clean and put a coat of paint over them. The pipe is getting a little thin but I'm not in any great rush to replace it.

It's not going to explode or crack out. If it's a rust thru hole it will eventually get larger.
It's a slow process.
 
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Old 05-01-18, 10:08 AM
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I think it's an eventual replacement. BUT... that eventuality could be 10-20 years from now.

Like Pilot Dane and Pete mentioned, give it a good wire brushing and keep an eye on it. It will eventually rust through, but I wouldn't bother doing anything until it happens. It's also on a vertical section, so you're not going to end up with a flood or anything horrible like that if/when it does start leaking for real.
 
 

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