Jonah,
Your best bet is to use the Valency check using the generic junctions feature class, which is created when you build your geometric network. A generic junction is created when there is a split in the line and no other junction (valve, fitting, hydrant, meter, etc) exists there.
The Valency Check is in the Advanced Check category.
Feature Class 1 = WaterDistribution_Net_Junctions
Feature Class 2 = wMain
Valency Operation = = (equal to)
Equal to = 2
Good Luck!