Preheat an oven to 350 degrees F (175 degrees C). Grease a tube pan or bundt pan.
Cream together butter and brown sugar. Add egg and water; blend well.
Mix together the flour, baking powder, baking soda, salt, nutmeg and cinnamon in a separate bowl; blend into the creamed butter mixture. Stir in the grated carrots and mix thoroughly. Pour evenly into prepared tube pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour.