Peel and pit the peaches. Finely chop them up. Measure out exactly 3 cups of diced peaches, and add them to a large bowl.
Add one cup of sugar to the bowl and stir it well. Add additional sugar 1 cup at a time. Stir in the lemon juice. Let the peaches sit for 10 minutes,
In a small sauce pan, add the water and fruit pectin. Bring the mixture to a rolling boil over medium high heat. Let it boil for 1 minute, stirring constantly.
Pour the pectin into the fruit mixture and stir for 3 minutes. Set a timer, stir longer if needed until the sugar is dissolved.
Pour the jam into the freezer safe containers, leaving 1/2 inch of space at the top.
Wipe the rims of the jars clean and cover them with their lids.
Let the containers sit at room temperature for 24 hours to set.
Store the jam in the fridge for up to 4 weeks, or freeze for up to 1 year.