Preheat oven to 350°F. Grease and flour two large (9 by 5-inch) loaf pans.

In a large bowl, whisk together the flour, baking soda, salt, and pumpkin pie spice.

In another large bowl, blend together the pumpkin puree, sugar, oil, water, eggs, and vanilla until well incorporated.

Slowly add in the flour mixture, stirring until just blended.

In a small bowl, stir together the sugar and cinnamon until well combined.

Divide three-quarters of the batter between the prepared pans. Sprinkle with about three-quarters of the cinnamon sugar, and use a butter knife to swirl through each loaf.

Divide the remaining batter between the pans and sprinkle with the remaining cinnamon sugar mixture.

Bake for 60 to 65 minutes, or until a toothpick inserted in the center comes out clean.

Cool bread in pans for 5 to 10 minutes and then carefully turn out onto a wire rack to cool completely.