Place the strawberries, water, and sugar in a large saucepan. Stir.
Bring to a simmer over medium heat.
When strawberries are soft, mash them with a potato masher.
Let strawberries continue to simmer gently until the juices begin to reduce, thicken and become syrupy. (reduce heat if needed)
Strain mixture through a mesh strainer, using a rubber spatula to press out the excess syrup. Discard the pulp. (You should have about 1 ¼ cups of syrup.)
Let syrup mixture cool and then place in the refrigerator until chilled.
To make a glass of soda, pour 8 oz of cold club soda into a cup. Stir in the chilled strawberry syrup by the tablespoon, tasting until you've reached your desired sweetness.