First thing when making the jam is to sterilize the jars and lids. Wash them thoroughly and make sure they are well dried before adding the jam inside. If you don't have a dishwasher with high temperature setting just wash the jars and dry them in the oven (275 F , 130 C) until completely dry and to keep them hot until the jam is ready. Put the lids into a pan of hot, but not quite boiling water for 5 minutes. Always sterilize more jars in case you got with more jam than you anticipated. Keep the jars hot to prevent them from breaking when you fill them with the hot jam.
Cut the fresh apricots in half and remove the pits. Place the apricots in a heavy bottom large pot and add the water and lemon juice. Cover and cook, stirring frequently, until apricots are soft and cooked through for about 50-60 minutes.
Put a small plate in the freezer.
Add sugar and cook, uncovered, stirring constantly until done. Remove any foam that rises to the surface.
Once you think the jam is thick enough, test it on the cold plate. Let it cool and if it crinkles and holds it is done. If not continue cooking and repeat the test until the right consistency.
Preheat oven to 300 F (150 C) .
Carefully fill your hot jars leaving 1/2 inch head space. Place the jars in a baking tray and place it in the oven. Add some warm water in the baking tray and let the jars in the warm oven for about 1 hr.
Remove them carefully to a cloth covered counter. Add the lids, cover with the cloth and let them cool on the counter.