Lady Umm Salamah (may Allah be pleased with her), the wife of the Prophet (peace be upon him), said that a woman came to the Prophet (peace be upon him) and asked: "I tie my hair in a braid on my head, what should I do?" He replied: "Pour three handfuls of water over your head, and after pouring each handful, rub (your hair)." (That is, rub the hair so that the water reaches the roots.)
Hadith Referenceسنن دارمي / من كتاب الطهارة / 1191