Cpl. Colbey Bentley says officers responded to a vehicle sinking at Settlement Canyon Reservoir shortly after 2 p.m.
Police say two officers happened to be nearby checking water levels when witnesses who saw the car sinking notified them.
Witnesses said there were three people in the car: a 43-year-old woman, a boy of unknown age, and a 12-year-old girl. They reportedly told the officers that the woman and boy had already escaped but that the girl was still trapped inside.
The car was now fully submerged in water at this time.
The officers attempted to enter the vehicle, and after exhausting all other measures of trying to do so, one officer shot his gun, shattering the window, and pulled the trapped girl out successfully.
The girl was unconscious when officers performed CPR. She then regained consciousness before being taken to the hospital where she has been listed in stable condition.
No further information is available at this time.