Combine the water, rice, cinnamon sticks, and salt in a large pot or Dutch oven over medium-high heat. Bring to a boil, reduce heat to low, cover, and cook for 15 minutes.
Stir in the milk and sugar. Bring to a boil, reduce heat to low, and cook for 25-30 minutes, stirring often until thickened.
Serve warm or refrigerate for 2 hours and serve cold.
Garnish with ground cinnamon, chopped nuts, or raisins if desired.
