In a small saucepan, bring 2 cups water, peaches and sugar to a boil. Reduce heat, cover and simmer for 5-7 minutes or until peaches are tender. Remove from the heat. Cool and strain. Gently peel and discard peach skins.
In a large pitcher, combine the peach mixture, lemon juice and remaining water. Add lemon slices and mint for extra flavor or on the glass as a garnish. Serve over ice.