Preheat oven to 350°F (175°C) and grease two 9x5 inch loaf pans.
In a large bowl, whisk together pumpkin puree, eggs, oil, water, and both sugars until smooth.
In a separate medium bowl, sift together flour, baking soda, salt, cinnamon, pumpkin pie spice, and baking powder.
Gradually stir the dry ingredients into the wet ingredients until just combined, ensuring no large flour pockets remain.
Divide the batter evenly between the two prepared loaf pans.
Bake for 60 to 70 minutes, or until a toothpick inserted into the center comes out clean.
Cool in pans for 10 minutes before transferring to a wire rack to cool completely.