Step 1: Combine hibiscus flowers and 4 cups of water in a saucepan. Boil over medium heat.
Step 2: Reduce heat, simmer for 10 mins. Turn off heat, let it cool completely.
Step 3: Strain into a bowl, pressing flowers. Transfer to a pitcher, add sugar, mix to dissolve.
Step 4: Mix in remaining water, adjust sweetness. Serve over ice or chill before serving.