Crews from the Northwest Fire District were dispatched Friday morning around 5:30 a.m. in reference to a drowning.
Adam Goldberg, spokesman for Northwest Fire, said the victim's husband called 911, saying he found his wife in the pool.
Upon arrival, Northwest fire crews found the patient out of the pool, assessed and she was pronounced dead.
Goldberg said the investigation has been turned over to the Pima County Sheriff's Office.
Tom Peine, spokesman for the sheriff's department, said the 56-year-old female, whose identity has not been released, is suspected of committing suicide.
A note was found near the scene, according to Peine.
Peine said the body was found around 5:25 a.m., and family members last saw her alive around 9:30 p.m. Thursday night.