Musannaf Ibn Abi Shayba 1:303

Yazid ibn Harun narrated to us, he said: Hammad ibn Zayd narrated to us, from Hisham ibn Hassan, from Muhammad, he said: Abu Bakr, Umar, and Uthman—according to what Abu Khalid knows—used to perform ablution for every prayer. And when they were in the mosque, they would call for a basin.