The bust is part of an ongoing effort to crack down on illegal grow operations that damage the environment.
The teams found two marijuana gardens near Page Mill Road with about 20,000 plants total. They also discovered two bags of ammo, but no gun, and a Taser-style weapon, Sheriff Sgt. Rick Sung said.
Several empty camping areas were also found in the gardens, Sung said.
The operation is an ongoing effort between the departments to crack down on illegal marijuana growers who cause severe damage to the environment by contaminating the water system with pesticides and littering the areas with trash and human waste.
A bust in late June in the Palo Alto hills netted 5,500 plants.
Drug agents say Mexican drug cartels have set up shop in Northern California because the topography is good for hiding the secret gardens and the climate is friendly to the plants.