A spokeswoman for the district said it happened around 7:30 a.m. near the intersection of Highway 114 and FM 156.
The driver was stopped at a red light and noticed the water rising fast around her. It splashed into the bus and pushed her off the road.
There were no students on board at the time.
The driver escaped unharmed through the bus' back door.
Flood warnings are in effect for several counties in North Texas.
According to the Associated Press, residents in about 150 homes near the rain-swollen Wichita River were forced to evacuate due to concerns over possible flooding.
FOX 4 viewers also reported high water in Fort Worth, Haslet, Justin, Rowlett, Seagoville and Wylie.