Is there an obligation of ghusl for a woman if she has a wet dream? He said: Yes, if she sees the water. The hadith is agreed upon by al-Bukhari and Muslim.

The Shaykh : We begin tonight’s lesson, if Allah wills, with the hadith: “Anas (may Allah be pleased with him) said:

The Messenger of Allah (peace and blessings be upon him and his family) said regarding the woman who sees in her dream what a man sees: She performs ghusl.

قال رسول الله صلى الله عليه وعلى آله وسلم في المرأة ترى في منامها ما يرى الرجل قال : تغتسل

It is agreed upon by al-Bukhari and Muslim.
Muslim added:

Umm Salama said, “Does this happen (to a woman)?” He (ﷺ) said: “Yes, otherwise where does the resemblance (of a child to its mother) come from?”

فقالت أم سلمة : وهل يكون هذا ؟ قال : نعم، فمن أين يكون الشبه ؟

Bulugh al-Maram 111

“ :
His statement: The Messenger of Allah (peace and blessings be upon him) said regarding the woman who sees in her dream what a man sees: This hadith was transmitted by the author by meaning, and its original source is:
:
So reflect on this noble etiquette of this woman, where she addressed the Prophet (peace and blessings be upon him) and preceded her address with what establishes her excuse, which is her saying: .
So the Prophet (peace and blessings be upon him) answered her: .
And the author (may Allah have mercy on him) omitted this phrase, even though it is a necessary requirement.
So the woman sees in her dream that someone is having intercourse with her, so does she perform ghusl or not?
Likewise, the man sees in his dream that he is having intercourse with a woman, so does he perform ghusl or not?
The Prophet (peace and blessings be upon him) specified that with a clear, distinct limit, saying: meaning: she saw the water which is janabah, i.e., semen, so she performs ghusl.