Why when i get water up my nose it doesn't drain down my throat.

Postural.: If your head is tilted forward, most of the liquid will drain back out of your nose; the rest may drain into your sinuses or eventually get reabsorbed into the lining of your nose.. You should avoid getting plain water up your nose as it can be irritating or force bacteria into your sinuses. If you're using a saline nasal spray, you should lean forward slightly then blow your nose gently.

Not a disease: If you can breathe through your nose without problem, the water not going to your throat is not a disease. There is no good to be gained from making water go to your throat from the nose.