I think that drinking plenty of water is good for you but i did read somewhere recently that it's perfectly possible to drink too much and create a new set of medical problems.
I'm Type 2 and started off with as a 10 and since then have maintained by HbA1c levels to 5.4 - the first after diagnosis was 5.6.
At the moment i'm dieting, so have drastically reduced my carb intake but usually, i keep my b.g stable (ish) by drinking several cups of water throughout the day and by low-carbing.
I start each day with the old fashioned type of porridge and a glass of water.
I only eat 'brown' carbs, which is wholemeal pasta, bread and rice. I avoid mashed potatoes wherever i can cos they send me too high.
Good luck with your progress and keep at it. Experiment to see how you go and if you can persude your GP to give you test strips, even better. Perhaps ask for one box of 50 and say you want to test twice a day - before lunch and 2 hours after your evening meal - and that you'll record the results to discuss with the GP at the next appointment.
And exercise! Go for a brisk walk, armed with a bottle of tap water (which is just as good as the expensive shop stuff).
Good luck!
bunty