Wrap water chestnuts with bacon, securing with toothpicks. Arrange on a large baking sheet. Cover with barbecue sauce. Marinate in the refrigerator 12 to 24 hours.
Preheat oven to 300 degrees F (150 degrees C).
Remove wrapped water chestnuts from the marinade and place on another large baking sheet. Bake 20 minutes in the preheated oven, or until the bacon is evenly brown but not too crisp.
