I am looking for a movie that I watched as a young kid. It was in the 80's, and the only thing I can recall is something about a girl going through a mirror (and/or drain) and swimming under the house and into the outside swimming pool, but she couldn't get out. I think there may have been a make-out scene in the beginning because I remember my dad making me hide my eyes. I know it's not much to go on but if someone could help that would be great! Thanks!
It might be the 1986 horror/comedy, House. As I recall, there was a suicide near the beginning - that may have been what your dad didn't want you to see. There was also a part near the end that involved the main character using the medicine-cabinet mirror as a portal, and he and his young son ended up surfacing in a backyard pool (it may have been a garden pond).
It could be Dario Argento's Inferno. I don't remember her going through a mirror, but she definitely swims under the house.
Rose Elliot, a poet living alone in New York City, finds an ancient book titled The Three Mothers. The book, written by an alchemist named Varelli, tells of three evil sisters who rule the world with sorrow, tears, and darkness, and dwell inside separate homes that had been built for them by the alchemist. Mater Suspiriorum, the Mother of Sighs, lives in Freiburg. Mater Lachrymarum, the Mother of Tears, lives in Rome, and Mater Tenebrarum, the Mother of Darkness, lives in New York.
Rose suspects that she is living in one of the buildings and writes to her brother Mark, a music student in Rome, urging him to visit her. Using clues provided in the book as a guide, Rose searches the cellar of her building and discovers a hole in the floor which leads to a water-filled ballroom. She accidentally drops her keys and enters the water to find them. After she reclaims the keys, a putrid corpse rises from the depths, frightening her. Rose manages to get away, but is being watched.