In a glass jar, combine 2 cups of water, 2 tablespoons of grated ginger, and 2 tablespoons of sugar. Stir well to dissolve the sugar.

Cover the jar with a cloth and secure it with a rubber band. Let it sit at room temperature for 3-5 days, stirring daily, until bubbly and active.

In a large mixing bowl, combine 1 cup of the prepared ginger bug, 4 cups of water, 1 cup of sugar, and the juice and zest of 1 lemon. Stir until the sugar is dissolved.

Using a strainer, pour the mixture into clean bottles, leaving some space at the top for carbonation.

Seal the bottles tightly and let them ferment at room temperature for 2-3 days. Check daily for carbonation.

Once carbonated, refrigerate the bottles to stop fermentation. Serve chilled.