It is narrated from Sayyiduna Anas (may Allah be pleased with him): The time of prayer came, so those whose houses were near got up and went to their families to perform ablution, and some people remained. A stone vessel used for dyeing clothes, with water in it, was brought to the Prophet (peace and blessings be upon him), and the vessel was so small that he (peace and blessings be upon him) could not spread his palm in it; even so, all the people performed ablution (from it). We asked: "How many were they?" He said: "More than eighty."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 117