In a medium saucepan, bring the water to a boil over high heat.
Remove the saucepan from the heat and place the tea bags into the hot water, making sure they are fully submerged. Allow the tea to steep for 10 to 25 minutes, depending on how strong you would like the flavor to be.
Gradually stir in the granulated sugar until it is completely dissolved.
Carefully remove and discard the tea bags.
Pour the sweetened tea concentrate into a 1-gallon heatproof pitcher.
Add enough cold water to fill the pitcher, and stir well to combine.
Refrigerate until chilled (about 4 hours, up to overnight)
When ready to serve, fill glasses with ice cubes and pour in the sweet tea.