Officers say a driver of an SUV told police she had to take evasive action before ending up in Sahoma Lake Wednesday morning.
Sapulpa Police said it happened on the west end of the lake near the intersection of South 161st Street West Avenue and West 91st Street South.
The driver told police, a white vehicle ran a stop sign causing the pickup to go into the water.
The driver and her 5-year-old grandson were treated by paramedics at the scene and released.
Police said a wrecker service was called to get the pickup out of the water.
An investigation into the accident continues.