A police officer guarding the residence was wounded, KTN News reported. NTV News said gunshots could still be heard from the scene.
NTV News also showed footage of heavily armed officers at the scene responding to the attack.
Police and officials from Ruto's office were not available for immediate comment.
The incident comes some 10 days before Kenya's presidential, legislative and regional county representative elections on Aug. 8.
Ruto's is President Uhuru Kenyatta's running mate. Kenyatta is seeking a second and final term in office.
The motive of the attack was unclear. Typically the deputy president's residences are heavily guarded by an elite paramilitary police unit.