Combine the water and sugar in a saucepan. Heat over medium, stirring occasionally, until sugar dissolves. Stir in jalapeño. Cover and let sit for 30 minutes, then strain the peppers from the syrup.
While the syrup is steeping, combine the lemon juice, water, salt, and jalapeño syrup in a pitcher. Stir until the salt dissolves, about 2 minutes. If you are adding jalapeño powder, add this to taste, stirring thoroughly to dissolve. Chill for at least 4 hours before serving over ice to further dilute it. Enjoy within 3 days!
Notes
Please use caution when chopping jalapeños. Avoid touching your face or eye area before washing hands thoroughly with soap. Wearing gloves while chopping any type of chile is highly recommended to avoid irritation.
Nutrition information is calculated using 1 cup of pure cane sugar.