The common symptoms of diabetes are significantly increased thirst, the need to urinate more often than usual, and increased hunger.
www.diabetes.co.uk
Your profile says you are a diet dependent T1, so am guessing you are at the early stages yourself. Did you have any symptoms? (Most/many T1s under 30 move to insulin fairly quickly, I believe.)
For me I was in hospital at the time and had a cold patch on my leg, then started drinking about 3 litres of water a day after leaving. Something didnt feel right so spoke to my GP who arranged blood tests.