Preheat oven to 350 degrees F (175 degrees C). Grease 8 muffin cups or line with paper liners.
Beat eggs together in a large bowl. Mix ham, bell pepper, onion, salt, black pepper, and water into the beaten eggs. Pour egg mixture evenly into prepared muffin cups.
Bake in the preheated oven until muffins are set in the middle, 18 to 20 minutes.