That's correct for water lines, and is expensive. But drain and sewer lines are in the slab. Just imagine the cost of removing your tile flooring, then cutting

That's correct for water lines, and is expensive. But drain and sewer lines are in the slab. Just imagine the cost of removing your tile flooring, then cutting up the slab, removing the usually copper drain line (on older homes), laying new PVC, back filling with sand or gravel, THEN recovering the floors. Carpet would be a little cheaper.