In a small sauce pan, add the blueberries and water.
Cook on medium heat for about 5 minutes or until mixture starts to boil.
Stir and crush the berries with a wooden spoon.
Cook for another 5 minutes until all the berries have lost their shape. Remove from heat.
Put a small strainer over a large glass measuring cup and let the juice strain through.
Use a spoon to help make sure all the juice goes into the cup. Discard solids or reserve for something else. You should have a cup or more of blueberry liquid.
Put the juice back in the pan with the sugar, pectin and lemon juice.
Cook on medium heat until mixture comes to a simmer.
Simmer for a few more minutes until jelly starts to thicken. More pectin can be added if you like a thicker consistency.
Pour jelly into a glass jar and cool for half an hour.
Cover and refrigerate until ready to use.