Nearly 3,000 marijuana plants were growing in each room of the underground grow-op, RCMP say.

A 61-year-old man has been arrested after police recovered more than 11,000 marijuana plants, worth an estimated $3 million, from a bunker buried beneath a rural property in the B.C. farming community of Chilliwack.

RCMP said it's too early to determine whether an organized crime group was responsible, but they are calling it one of the largest, most sophisticated grow-ops they've discovered in the area, which is known as a hotbed for marijuana grow-ops.

"A lot of time and effort went into setting this up. We don't yet know if there are any links to organized crime, but we can definitely say that a number of people were involved with establishing this grow-op," Chilliwack RCMP Cpl. Leanne Dunlop said.

Elevator accessed underground bunker

The grow-op was found on a property in the hills east of Chilliwack, which is in the Fraser Valley east of Vancouver. The operation was buried beneath a Quonset hut, a long shed with a semi-circular cross section.

Inside the hut, a concealed elevator installed beneath the floor provided access to four underground rooms, each holding about 3,000 plants.

Police said the grow-op was likely functioning for several years, and they estimated more than $400,000 of electricity was illegally diverted from nearby power wires to keep the lights, fans and hydroponic equipment running over that time.

A nearby stream was also diverted to water the marijuana, and video surveillance cameras were installed to monitor the operation from a nearby house, while booby traps of bear spray had been installed to protect it.

Dunlop said the 61-year-old man they arrested was not the subject of any other police investigations before he was taken into custody.

Neighbours noticed smell

The property was located on the 7600 block of Nixon Road. Neighbour Janet Zinck was stunned there was such an elaborate set-up near her home.

"The owner of the farm up there … I wouldn't have imagined it, but how do you know? You just don't know these things. Meeting him he seemed very nice, and so did the two workers.... That's the shock of it all," she said.

Zinck said she believes it was the odour from the property that tipped off police.

"That smell of skunk was obviously a warning. That's why the constables came up earlier this year," she said.

Tony Thompson, who also lives in the area, said he wasn't shocked by the revelation of a major drug operation so close to home.

"It's an ideal setting, so it doesn't surprise me at all," he said.