If you see this black pipe sticking out of the ground somewhere - this is a key indicator that the property has probably done major upgrading to the plumbing to #absplumbing. This is the current gold standard piping. If you are buying a home build BEFORE the 1980s odds are that it has #castiron plumbing. Cast iron plumbing is now reaching the end of its life span and if it corrodes after you buy your home it will be a MAJOR expense; furthermore this item is typically not covered by insurance or home warranties.
To know for sure have your home inspector or plumber do a camera inspection during your contingency period to visibly examine all they piping to determine if the current owners have replaced the old cast iron with new ABS plumbing. This is a major expense and major construction piece that has already been taken care of for you and should well outlast your life span.
How much does removing old cast iron pipes and replacing them with abs cost?
This will vary on how many linear feet of replacement is needed, and how deep it is in the soil or if its located in a concrete slab. Many times it could cost upwards of $10,000.