It can be considered a healthy drink depending on what type and how much sugar you use to sweeten it. Using a natural sweetener (like agave) or honey is the healthiest option.  Lemon juice on its own is full of vitamin C and promotes hydration. Watermelon contains mostly water, but it’s full of vitamins like A, B6, and C, lycopene, as well as antioxidants. Because watermelon is made mostly of water, This delicious drink will definitely keep you hydrated during the heat of summer!