Boil potatoes in salted water until tender, about 10-15 minutes. Drain and let cool slightly.
In a large bowl, mix ranch dressing, mayonnaise, garlic powder, salt, and pepper until combined.
Add the cooked potatoes, crumbled bacon, and green onions to the bowl. Toss gently to coat.
Refrigerate for at least 1 hour before serving for flavors to meld together.
Garnish with chopped parsley before serving, if desired.