WHAT TO LOOK FOR
Large piles of dirt along garages, around outbuildings, sides of houses, or ground-level decks can be a very good indication of groundhog activity. Groundhogs spend a large amount of each day basking in the sun, and are very alert when feeding, readily darting back to the burrow or under outbuildings. They will also leave a large amount of droppings.
The most effective method is to remove all the groundhogs, and then exclude them from ground level decks and outbuildings. Backfilling as much as possible of the burrow will help reduce other animals occupying vacated burrow systems.