Place the fruit in a large, heavy saucepan. Add the water and simmer on medium heat, mashing and stirring from time to time, for 30 minutes, or until softened.
Reduce the heat to low, and add the sugar, stirring until dissolved completely. Bring to the boil and boil for 20 to 30 minutes. Test the jam to see if it's set; if setting point has not been reached, boil for 5 minutes more, then test again.
Pour jam into jam jars and secure with lids immediately.
How to test for setting
Test for setting by spooning a small amount onto a chilled saucer. Chill for 3 minutes, the push the jam with your finger; if wrinkles form on the surface, it is ready.