Abu Dawud said I heard Qutaibah b. Sa'id say: I asked the person in charge of the well of Bud'ah about the depth of the well. He replied: At most the water reaches pubes. Then I asked: Where does it reach when its level goes down ? He replied: Below the private part of the body.
Abu Dawud said: I measured the breadth of the well of Buda'ah with my sheet which I stretched over it. I them measured it with the hand. It measured six cubits in breadth. I then asked the man who opened the door of garden for me and admitted me to it: Has the condition of this well changed from what it had originally been in the past ? He replied: No. I saw the color of water in this well had changed.
In-book : Book 1, Hadith 67
English translation : Book 1, Hadith 67