Hello, I ve read your description carefully but unfortunately, the information is not enough to reach a solid conclusion. I can, however, suggest potential causes starting with the most common ones and I m going to comment on the diabetes issue that you ve mentioned. Polydipsia (excessive thirst) usually occurs as a result of dehydration or psychological causes. Dehydration may occur with diabetes mellitus and diabetes insipidus, use of diuretics and other drugs that induce increased urine production and excessive loss of water (sweating for example when engaging into a lot of strenuous physical activities). Regarding your family history, it does increase your individual risk for diabetes but if you ve got normal glucose - even a year ago - then it s unlikely that you now have such a high glucose level that causes excessive urination. You should check your blood sugar again though. Checking the serum electrolytes, urine and creatinine are other indices that may help with the diagnosis. A urinalysis may provide additional information regarding the functional status of your kidneys. Most patients that drink too much water, do so because of psychological reasons. They have an urge or compulsion to drink water all the time or when they re stressed. If testing does not reveal any causes then psychogenic polydipsia may be suspected. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Panagiotis Zografakis, Internal Medicine Specialist