Place bacon in a skillet over medium-high heat and cook until evenly browned. Remove bacon with a slotted spoon; drain on paper towels. Crumble bacon and set aside. Keep bacon drippings in the skillet.
Mix eggs, milk, water, salt, and pepper in a bowl until combined.
Add potatoes to bacon drippings in the skillet and cook over medium heat until semi-soft. Stir in onions. Cook and stir for 1 minute. Pour egg mixture into the skillet. Stir in crumbled bacon and butter. Cook until eggs set to your desired firmness.