Put the blueberries with the rosemary in a carafe or glass bottle. Drizzle with the maple syrup and fill up with the water. Let the water steep for about 6 hours and then enjoy.
Tip: If you take frozen berries, they give off more flavor to the water. If you don`t have enough time to let it steep, pour a splash of hot water over the ingredients. Only then add the remaining water to the ingredients.