Musnad Ahmad 358:1

Abu Nuh narrated to us, he said: Malik informed us, from Sumayy, from Abu Bakr ibn Abd al-Rahman ibn al-Harith ibn Hisham, from a man among the companions of the Prophet, may Allah bless him and grant him peace, who said: "I saw the Prophet, may Allah bless him and grant him peace, pouring water over his head at al-Suqya, either because of the heat or because of thirst, while he was fasting. Then he remained fasting until he reached Kadid, then he called for water and broke his fast, and the people broke their fast, and that was in the year of the Conquest."