It was the practice of the Prophet (peace and blessings be upon him):
"He (peace and blessings be upon him) would perform the ritual bath (ghusl) with one sa' of water and perform ablution with one mudd of water."
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4991
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[ق د] عن أنس. صحيح أبي داود ٨٢، الإرواء ١٣٩.