Assuming you are referring to single house residential in your question. Are you buying the property from a bank owned/REO, a short sale seller, or a court steps auction? Bank owned, short sale, or regular sales have to have clean title to transfer to a new buyer meaning if there were liens, they will need to be paid before escrow is closed. Title/escrow will check for any liens on the property. If you buy and an auction, you have to know what you are doing and do your homework, check the records because it may still have liens on it, then you would be responsible for the unpaid liens.