It was narrated from Abu Sa'eed Al-Khudri that the Messenger of Allah (ﷺ) said:
"The land around a well (that is considered to be part of it) is the length of the well rope (in all directions)." (TR)
English reference (TR): Vol. 3, Book 16, Hadith 2487 (TR)
Arabic reference (TR): Book 16, Hadith 2581 (TR)