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.'" (RU)
English reference (RU): Vol. 1, Book 1, Hadith 198 (RU)
Arabic reference (RU): Book 1, Hadith 199 (RU)