Peel, pit, and finely chop peaches. Measure exactly 3 cups of prepared fruit into a large bowl. Use a masher to further break down the peaches if desired.
Combine peaches, sugar, and lemon juice in a bowl. Let stand for 10 minutes, stirring occasionally.
Meanwhile, in a saucepan, mix water and pectin, bringing it to a boil. Cook for 1 minute, then add to the fruit mixture. Stir until pectin is well incorporated.
Pour the mixture into cleaned jars, leaving ½ inch of space at the top. Cover with lids.
Let stand at room temperature for 24 hours, then refrigerate for up to 3 weeks or freeze for up to 1 year.
