It was narrated that Khawlah bin Hakim said:
"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.'" (JA)
English reference (JA): Vol. 1, Book 1, Hadith 198 (JA)
Arabic reference (JA): Book 1, Hadith 199 (JA)