Drexel Heights Fire District responded to a drowning call in the 5100 block of south Spencer Monday.
According to DHFD, the victim's parents called 9-1-1 after they found their 18-year-old daughter at the bottom of their backyard swimming pool.
DHFD paramedics arrived and performed CPR. She was then transported to a nearby hospital where she was admitted and is now in the ICU.
Authorities say that she was a strong swimmer who was in the pool daily and has no medical concerns.
This is the seventh water incident in Pima County in 2017.