What is the ruling on drinking water when intending to fast, while doubting whether it was before or after dawn?

Whoever intended to fast and ate before Fajr, their fast is valid. As for whoever ate after the appearance of Fajr, thinking it had not yet appeared, then it became clear to them that it had, their fast is not valid, and they must make it up if it was an obligatory fast. If one doubts the appearance of Fajr and it does not become clear to them that it has appeared, their fast is valid.