Question: how much water to cook 1/2 cup farro?
Answer: Rinse the farro with water.
Add 1 cup farro to a pot with 3 cups of water.
Boil and then reduce heat to a simmer.
Cook until the grains are tender, about 30 minutes.
For faster cooking, the farro can be pre-soaked in water overnight in the refrigerator. ... 
Drain the water and then use as desired.