In a large skillet, cook Italian sausage until browned, or about 3-5 minutes. Drain if desired. Stir in water, pasta, tomato sauce, ½ cup pepperoni, basil, oregano, and garlic powder, and bring to a boil. Reduce heat, cover, and simmer until pasta is cooked through, about 10-12 minutes. Season to taste with salt and pepper. Remove from heat. Top with remaining pepperoni and mozzarella. Cover immediately with foil until cheese is melted, or about 2 minutes. Garnish with fresh parsley, and serve!