Clean and chop rhubarb stalks into 1/2" chunks.
In a medium saucepan, combine chopped rhubarb, sugar, and water. Stir to combine.
Bring to a boil and then decrease the heat to a low-medium simmer. Continue cooking for 40 minutes to 1 hour, until the mixture thickens.
Allow the rhubarb mixture to cool for 20 minutes.
Using a medium bowl, cut a piece of cheesecloth large enough to fit over the bowl. Pour the rhubarb mixture over the cheesecloth and pull up the cloth to make a balloon around the liquid.
Gently squeeze the "balloon" of rhubarb until all/most of the juice has been extracted.
Store the syrup in a mason jar and refrigerate.