"I asked the Messenger of Allah (ﷺ) about a woman who has a wet dream and he said: 'If she sees water, let her perform Ghusl.'"
Sunan an-Nasa'i Book 1, Hadith 199
← Previous Hadith "O Messenger of Allah, Allah is not shy to tell the truth. Does a women have to perform Ghusl if she has a wet dream?" He said: "Yes, if she sees water." Umm Salamah laughed and said: "Do women really have wet dreams?" The Messenger of Allah (ﷺ) said: "How else would her child resemble her?" That is, if she has an emission of the fluid of an orgasm.

Sunan an-Nasa'i Book 1, Hadith 198 Next Hadith → "Water is for Water." That is, water for peforming Ghusl is obligatory when the ejaculation of water (semen) occurs.

Sunan an-Nasa'i Book 1, Hadith 200