[arcwick08]

Hey fellas (ladies too),

I've got a small ranch house with 4inch cast iron waste pipe. When we bought the house, the inspector said the pipe would need replacing "soon". We've been in the house about a month now with no escaping sewage.

What are some tell-tale signs of cast-iron pipe being just about to rot through? Anything visible from the outside of the pipe?

[ballengerb1]

Spots of rust and weeping will be your first sign. That or the pipe will clog because it has collapsed under the floor or outside.

[Milo Dolezal]

As cast iron ages, it flakes off. If you knock on it, it should sound solid. Take a hammer and gently tap on it in one place. You will feel if the hammer bounces off like from a piece of healthy metal or from piece of pipe that is in advanced stages of deterioration.

[ballengerb1]

We call Milo's test PLINKING. If you hear a nice plink with the hammer you are OK, if there is little bounce and more like a thund you have some work to do.

[arcwick08]

All right, some sections have a nice ringing "boink" sound when tapped, others have a hollow knocking sound. These sections have some visible rust and these funny little... well... nipple-looking things hanging off the bottom of the pipe.

[ballengerb1]

I think you are a candidate for a replacement line. Most of us would recommend PVC but this may be more than a DIY job. Get 3 bids from plumbers and then decide if you can do it yourself.