Sheriff's officials initially issued an alert shortly before 12:15 p.m. about the response to the school, which resulted in a lockdown with multiple law enforcement agencies assisting.
An image from a video sent by Meredith Rennie shows people standing at the scene.
The Sheriff's Office asked parents to not come to the campus while the investigation was ongoing.
Authorities determined the threat to the school was not credible.
School officials said all staff and students are safe.
KGO-TV/ABC7 Eyewitness News contributed to this report
If you're on the ABC7 News app, click here to watch live