Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
bukhari:255 – Muḥammad b. Bashhār > Ghundar > Shuʿbah > Mikhwal b. Rāshid > Muḥammad b. ʿAlī > Jābir b. ʿAbdullāh

The Prophet ﷺ used to pour water three times on his head.  

البخاري:٢٥٥ – حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ قَالَ حَدَّثَنَا غُنْدَرٌ قَالَ حَدَّثَنَا شُعْبَةُ عَنْ مِخْوَلِ بْنِ رَاشِدٍ عَنْ مُحَمَّدِ بْنِ عَلِيٍّ عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ قَالَ

كَانَ النَّبِيُّ ﷺ يُفْرِغُ عَلَى رَأْسِهِ ثَلاَثًا  

See similar narrations below:

Collected by Nasāʾī
nasai:426 – Muḥammad b. ʿAbd al-Aʿlá > Khālid > Shuʿbah > Mukhawwal > Abū Jaʿfar > Jābir

"When the Messenger of Allah ﷺ performed Ghusl, he would pour water on his head three times."  

النسائي:٤٢٦ – أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى قَالَ حَدَّثَنَا خَالِدٌ عَنْ شُعْبَةَ عَنْ مُخَوَّلٍ عَنْ أَبِي جَعْفَرٍ عَنْ جَابِرٍ قَالَ

كَانَ رَسُولُ اللَّهِ ﷺ إِذَا اغْتَسَلَ أَفْرَغَ عَلَى رَأْسِهِ ثَلاَثًا