Noah Schlenk was doing morning laps in the LA Fitness pool in north Seattle when something large crashed into the lane next to him.
At first he thought someone had thrown something into the pool. It turned out to be a car.
A vehicle crashed into the building around 8 a.m. Three people were in the pool at the time. No injuries were reported.
The car was almost completely submerged. Schlenk said the driver looked like he was in shock as he and another witness worked to pull him out of the vehicle.
First responders have not released details on the cause of the crash.
No arrests have been made in connection with the incident.
Most of the gym reopened around to clients around 4 p.m. Monday. The pool will remain closed for now as clean-up continues.