I have type 1 diabetes and my tougne has a white coating on it now and i don't know what to do about it and i tried to drink water but it not helping?

Probably fungus: infection. Your doctor should be able to tell for sure. by looking at it. If it is confirmed, treatment is usually anti-fungus mouth wash. Drinking water would probably not help.

Tongue coating: Often this due to change in the flora of the mouth. Try yogurt and probiotic. Also use xylitol chewing gum. Get your blood chemistry checked for anemia. For my patients I have them make a 2% solution of xylitol and use the Hydro Pulse Throat irrigation daily. Reflux can also be a cause. See www.grossaninstitute.com