(a) Abdullah bin Amr bin al-As (may Allah be pleased with them both) says: When the water amounts to forty large jars, nothing makes it impure.
(b) Abd al-Rahman bin Abi Hurayrah (may Allah have mercy on him) narrates from his father (may Allah be pleased with him) that when the water amounts to forty large jars, it does not carry filth. Others have differed from him; they say: forty large buckets. Some say: 'dalw' (buckets).
(c) It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that if there are forty buckets of water, nothing makes them impure, even if a person in a state of major impurity (junub) bathes in it and another follows him; and this (version) is more correct. Ibn Lahi'ah is not used as proof.
(d) In the hadith of the two qullahs, following the Companion whose saying agrees with the saying of the Messenger of Allah (peace and blessings be upon him) is more fitting.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1249