Depends what you mean by a lot. Lots of water can kill you, as the Titanic passengers discovered.
Don’t be taken in by daft instructions about having to drink so many litres in a day. You need to keep reasonably well hydrated, diabetic or not. It matters not whether you use water, tea, beer or lager. Your body will use just as much water as it needs. The best guide is the colour of your urine. Pale yellow is fine. Dark yellow/brown isn’t, neither is colourless urine.
Another good guide, believe it or not, is thirst. If you’re thirsty, drink some liquid till you aren’t.
Diabetics don’t need to drink any more than anyone else. They only drink more when the Blood glucose is high, because that makes you thirsty. The raised blood sugar means that the kidneys produce more urine to rid the body of the glucose, so you need to top up the fluid loss.
So the answer to the question you posed is it isn’t.🙂