Mix together the water, granulated sugar, brown sugar, pumpkin puree, cinnamon, ginger, nutmeg, and cloves together in a saucepan. Heat on medium-high and stir well.
Stir continuously as the mixture heats up and the sugar begins to dissolve. Do not let the mixture boil.
Remove the mixture from heat once the sugar is fully dissolved and allow to cool. Stir in the vanilla.
Strain the mixture in a fine mesh strainer lined with cheesecloth, then store the syrup in an airtight container.
Notes
You can substitute the spices for a premade pumpkin spice blend.