Musannaf Ibn Abi Shayba 13:1393

Abu Bakr narrated to us, he said: Mu'tamir narrated to us, from 'Adi ibn al-Fudayl, he said: I came to Umar ibn Abd al-Aziz and asked him to dig a well. He said: "Write down its protected area (harim) as fifty cubits, and it shall not infringe upon the right of a Muslim, nor shall it harm him, and the wayfarer is the first to drink."