My kitchen sink drain pipe is cracked and rotten. My plumber wants to run it down the hall to the main line. My house is old and since the drain pipe is cast iron we are assuming all the pipes in the house are. What are the chances we run the pipe down the hall just to find out the main line is rotten?

Hello, Myklebustk... you have to look at it this way: All the pipes in your house have probably been installed at the same time. Therefore, they deteriorate same length of time. Some parts may go faster, other parts, like vents, will last longer. I personally think it is a good idea to replace as much as you can afford. That's especially true about kitchen drain...

Let me know what you decided to do... Back to you... Milo