I observed Sawm (Fast) on a day

Q 1: Waking up on the night of 17-18/9/1407 A.H., I recognized that this was the time of Fajr (Dawn) Prayer. Yet I could not distinguish whether the light of dawn had appeared or not because the crescent was still apparent and there was no clear distinction whether the light of dawn had appeared or not. It was about half past four at the time. I am from the inhabitants of the city of Bishah. Feeling thirst, I drank a glass of water. Yet it became clear to me that most Mu'adhins (callers to Prayer) had already announced Adhan (call to Prayer) and that people had abstained from having food and drink. Should I make up for this day or offer Kaffarah (expiation)?

(Part No. 10; Page No. 293)  A: If the reality is as you mentioned, then you have to make up for this day because it is clear that you drank water after dawn.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.