It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that a man asked him: "How much water is sufficient for me for ablution?" He said: "One mudd." He asked: "And how much water is sufficient for me for bathing?" He said: "One sa’." The man said: "This amount of water is not sufficient for me," He replied: "May your mother lose you! This amount was sufficient for the one who was better than you," by which he meant the Messenger of Allah (peace and blessings be upon him).
It is narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "Two ritl of water are sufficient for ablution (wudu)."
It is also narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, would perform ablution with a vessel that contained two ratl of water, and he would perform ghusl with one sa’ of water.
It is also narrated from Sayyiduna Anas (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: "A mudd of water is sufficient for you for ablution."