It was narrated from Abu Ayyub that the Prophet (ﷺ) said:"Water is for Water." [1] [1] That is, water for peforming Ghusl is obligatory when the ejaculation of water (semen) occurs
Hadith No. 199
Sunan an Nasai
Gradings:
Abu Ghuddah:
Sahih
Al-Albani:
Sahih
Zubair Ali Zai:
Sahih