Is it the owner's responsibility to have a septic tank inspected before a sale of the home? Or does this fall on the new buyer's shoulders?
It's typically the buyer who hires a professional to inspect the septic system. If the inspection reveals that cleaning or repair is required, it could become the home seller's responsibility, depending on the language of the contract.
In terms of necessity, it's absolutely in the best interest of a buyer to have a septic tank and field thoroughly inspected by a licensed public health official prior to closing. Septic fields especially, if they fail, can be very, very expensive to replace.