Feeling thirsty all the time? Just a habit? Or diabetes? Otherwise no additional symptoms.

Possibly diabetes. When someone with diabetes mellitus has blood sugar levels over 180 mg/dl, the kidney loses sugar into the urine, which in turn draws out excessive fluid into the urine. This makes a person empty bladder often, frequently producing sugary urine. Excessive urination leads to dehydration, which leads to excessive thirst. If you stop drinking fluid and still produce lots of urine, get checked for dm!