In a large pot, bring the water to a rolling boil. Remove from heat. Drop the tea bags into the water. cover with lid and allow the tea bags steep for 1 hour.
Once the tea has been steeped, remove tea bags and add the sugar and lemon. Stir until sugar is completely dissolved. Pour into a 4 quart pitcher and add ice cubes or cool water until the volume has returned to 4 quarts. Refrigerate at least 4 hours (is better the day after).