I heard that the people asked the Prophet of Allah (ﷺ): Water is brought for you from the well of Buda'ah. It is a well in which dead dogs, menstrual clothes and excrement of people are thrown. The Messenger of Allah (ﷺ) replied: Verily water is pure and is not defiled by anything.
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.
Purification (Kitab Al-Taharah) - Sunan Abi Dawud 67
I heard that the people asked the Prophet of Allah (ﷺ): Water is brought for you from the well of Buda'ah. It is a well in which dead dogs, menstrual clothes and excrement of people are thrown. The Messenger of Allah (ﷺ) replied: Verily water is pure and is not defiled by anything.
Scholarly Commentary
This hadith establishes the fundamental principle that water in its natural state remains pure and cannot be rendered impure by external contaminants falling into it. The well of Buda'ah contained various najasat (impurities), yet the Prophet declared its water pure for ritual purification.
The scholars explain that flowing water or large quantities of water (over two qullah, approximately 500 ratl) do not become impure unless their taste, color, or smell changes substantially. The well's depth and breadth mentioned by Abu Dawud indicate it contained sufficient quantity to maintain purity despite impurities.
This ruling reflects the Islamic principle of easing difficulties in worship and avoiding unnecessary restrictions. Water's inherent purity is maintained unless definitively altered, allowing Muslims to use natural water sources without excessive concern about potential minor contaminants.
Juridical Implications
This hadith forms the basis for the majority position that large bodies of water remain pure despite contact with impurities, provided the water's essential qualities remain unchanged.
The Maliki school holds a stricter view, considering any water touched by impurity as contaminated. However, the Hanafi, Shafi'i, and Hanbali schools follow the principle established here, with minor differences in quantifying "large" bodies of water.