Generally speaking, a homeowner pays the full property taxes if the home is not the primary residence. (Some states offer to reduce the property taxes if the home is the primary residence; this is known as a homestead exemption.)

On top of the property taxes, the homeowner also pays insurance (home + hazard + flood) and the mortgage (principal + interest). If the home is part of an HOA, monthly fees to the HOA are also due. At all times the homeowner is responsible for the full upkeep of house. For example, tree trimming, fence repair, lawn maintenance, etc.

If troublemakers identify a house that remains empty most of the year, be prepared for them to move in secretly and indulge in nefarious activities (like setting up a marijuana grow operation in a state where that is illegal).

All in all, an empty property is a headache to maintain. A professional property manager helps, at which point you may as well rent the damn thing out.