Sa'id bin al-Musayyab (may Allah have mercy on him) says that the Messenger of Allah (peace and blessings be upon him) said: "The boundary zone of an ancient well is fifty cubits, and the boundary zone of a new well is twenty-five cubits." And Sa'id bin al-Musayyab (may Allah have mercy on him) said on his own: The boundary zone of a well for crops is three hundred cubits.
It has also been narrated through Ma'mar and Ibrahim bin Abi Ablah, from al-Zuhri, from Sa'id, from Abu Hurayrah, as marfu' and connected, and that is da'if (weak).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب إحياء الموات / 11870