It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) called for a vessel of water, and a wide, shallow cup was brought with a little water in it. He (peace and blessings be upon him) placed his fingers in it, and I began looking at the water, which was gushing forth from between his (peace and blessings be upon him) fingers. I estimated that those who performed ablution from it (that vessel) were between seventy (70) and eighty (80) (people).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 119