Critics cite the hadith of the Well of Budaah and claim it shows the Prophet (PBUH) taught Muslims to perform wudu with filthy water. It teaches no such thing. The hadith is a legal ruling about a well whose water had not been altered by impurity, not permission to wash with sewage, visible filth, or water whose smell, color, or taste has been corrupted.
The hadith
Abu Said al-Khudri reported that the Prophet (PBUH) was asked whether wudu could be made from the Well of Budaah. The questioner described it as a well into which things such as menstrual rags, dog flesh, and putrid matter were cast. The Prophet (PBUH) replied:
إن الماء طهور لا ينجسه شيء
Indeed, water is pure and purifying; nothing makes it impure.
Sunan Abi Dawud 66
The word tahur means water that is pure in itself and valid for purification. This report is not fabricated. Its chains were discussed by hadith scholars, but al-Tirmidhi graded it hasan, and many hadith and fiqh authorities cited it as evidence. The correct question is not whether the hadith exists, but how its general wording is understood with the rest of Islamic law.
It was not permission to pollute wells
Some translations render the description as things being "thrown" into the well. Even if that wording is used, the hadith is describing the situation about which the Prophet (PBUH) was asked; it is not commanding, praising, or permitting people to use water sources as dumps.
In fact, the Prophet (PBUH) explicitly forbade polluting standing water:
None of you should urinate in standing water that does not flow, then wash in it.
Sahih Muslim 282
If urinating in stagnant water is forbidden, then deliberately turning a well into a place for filth and carcasses is obviously not a Prophetic teaching. The Budaah hadith answers a different legal question: if impurity reaches a water source, is the water automatically impure, even when the water itself has not changed?
Contact with impurity is not the same as changed water
Classical jurists distinguish between mere contact with najasa and water that has actually been changed by najasa. They agree that if impurity changes one of the water's taste, color, or smell, the water is impure and cannot be used for purification.
Precision matters here: a narration ascribed to the Prophet (PBUH) with the exact exception, "except what changes its smell, taste, or color," is weak as a hadith. However, the ruling itself is not weak. The consensus of the jurists is that water changed by impurity in taste, color, or smell is impure.
Therefore the hadith does not mean: "Use water even if it has become foul." It means that water, especially a sizeable water source such as a well, is not ruled impure merely because impurity reached it, so long as the impurity did not alter the water itself.
The two qullahs report
Another hadith gives a practical indicator for a sizeable amount of water:
If the water reaches two qullahs, it does not carry impurity.
Sunan Abi Dawud 63; Jami at-Tirmidhi 67
A qullah was a large water vessel, and jurists discussed its exact volume. Many jurists, especially in the Shafii and Hanbali schools, used the two-qullah report as a threshold: below it they were stricter about impurity contacting water, while at or above it mere contact with impurity does not make the water unusable unless the water changes. Other jurists define "large water" differently, but the central point remains: a well or sizeable body of water is not treated like a small cup or bowl.
This report also does not override the agreed rule about changed water. If a large body of water is changed by impurity, it is impure. If it is not changed, it remains pure and purifying.
Water is the Quran's means of purification
...and He sent down upon you from the sky water by which to purify you.
Quran 8:11
Islam treats water as a blessing and a primary means of cleanliness. Its law avoids two extremes: it does not allow people to use genuinely foul water for purification, and it does not impose obsessive hardship by declaring an entire well or river impure because a contaminant reached it without changing it. Nor does Islamic law require a person to use water that is harmful.
Conclusion
The hadith of the Well of Budaah establishes a precise rule of purity law: mere contact with impurity does not automatically make a sizeable water source impure, but water changed by impurity in taste, color, or smell is impure. Far from telling Muslims to make wudu in filth, the hadith reflects the balance and reasonableness of Islamic purification law.
For the wider rulings on purification and impurities, see the related topics below.