I noticed cracks in the walls getting larger and called someone to check on the foundation. The foundation is fine (it's previously been repaired) but the center of the house is sinking. I plugged the outside drain line and did a leak test, and the water level in the shower drain dropped pretty quickly, so I'm pretty sure there is a leak.
My house was built in the 60s and I'm told it should have iron drain pipes. I assume the problem is a pipe running through the foundation to the outside sewer line. What is going to be involved in replacing the drain pipes? Am I going to have to tear up the floors all over my house to get all of them?
EDIT: I should add that this is Texas, so I don't have a basement.