Authentic German Potato Salad

Place the potatoes into a pot, and fill with enough water to cover. Bring to a boil, and cook for about 10 minutes, or until easily pierced with a fork. Drain, and set aside to cool.
Place the bacon in a large deep skillet over medium-high heat. Fry until browned and crisp, turning as needed. Remove from the pan and set aside.
Add onion to the bacon grease, and cook over medium heat until browned. Add the vinegar, water, sugar, salt and pepper to the pan. Bring to a boil, then add the potatoes and parsley. Crumble in half of the bacon. Heat through, then transfer to a serving dish. Crumble the remaining bacon over the top, and serve warm.