A phone rings in an office with no sign in a San Jose industrial park, and a caller places an order for delivery. But it’s not your ordinary delivery service — the caller wants pot, not pizza.

A driver for the Green Access collective then loads packages of marijuana bearing names of strains like Bubble Berry and Grapefruit and heads out, often to San Mateo County, to make a delivery in what is an increasingly common way for medical marijuana to change hands.

But whether it’s legal or safe depends on whom you ask. One thing many experts do agree on is that demand for delivery service is going to grow as people discover it.

After the Obama administration signaled that federal authorities would stop raiding medical marijuana dispensaries complying with California law, several dispensaries have tried to open in San Mateo County in the past year and failed.

So delivery services are stepping in to fill the void, experts said, setting up a clash with law enforcement.

That’s because many cities in San Mateo County are trying to regulate medical marijuana dispensaries or keep them out altogether.

San Mateo County’s lone dispensary faces closure after being denied a license. And most Peninsula cities, including Redwood City and South San Francisco, have enacted temporary bans while they consider the issue. Only San Mateo, San Carlos and the unincorporated areas of San Mateo County have ordinances that allow them.

While cities and dispensaries battle over whether they can operate on the Peninsula, the number of delivery services is quietly building.

About 14 services offer to bring medical marijuana to homes in the South Bay and the Peninsula. At least two of them are based in San Mateo County, but many more are from other parts of the region, with one offering to deliver directly from a farm in Mendocino County.

It is no surprise that delivery is becoming a popular option on the Peninsula, said Kris Hermes, spokesman for medical marijuana advocacy group Americans for Safe Access.

Delivery services are particularly pervasive in areas where authorities have clamped down on dispensaries, he said.

There are other attractions to home delivery for medical marijuana buyers. Experts said it is easy and private, and the price is about the same as in dispensaries.

“It just seems logical that it will expand,” said Martin Mayer, attorney for the California Police Chiefs Association. “It’s convenient. We’re lazy people.”

For Farsh Fallah, head of operations for Green Access, the decision to open a medical marijuana delivery service instead of a dispensary was a logical step. City councils up and down the Peninsula denied him permission to open a club before he gave up and started his delivery operation in San Jose in December.

Fallah said he screens people who order marijuana from him and limits the amount of cash and marijuana that drivers carry to ensure safety. So far nothing bad has happened; he will soon begin accepting credit card payments to add another layer of security for drivers.

But to Cmdr. Marc Alcantara, who heads San Mateo County’s narcotics task force, delivery services are dangerous for all involved: A driver can be sent to a phony drop-off where crooks wait with guns to rob him. Medical marijuana prescription holders can be ripped off by an unscrupulous service or get less than what they paid for.

Though he said there haven’t been any reported cases of medical marijuana deliverers being held up on the Peninsula, plenty of grow operations have been robbed.

“You can have a predator who robs the money and steals the product,” Alcantara said.

But personal safety is one of the benefits of deliveries for a 37-year-old San Mateo resident, who asked that her name be withheld to protect her privacy.

She said she didn’t feel quite safe walking out of medical marijuana dispensaries in San Francisco or Oakland with a bag of cannabis. While she has never heard of anyone getting mugged, that possibility of “let’s jump them and take their stuff” was always in the back of her mind.

Also, by ordering and having it delivered to her home, she avoids the possibility of running into somebody on the street, like a boss or co-worker, who would question what she was doing.

“I feel safer,” said the woman, who began using medical marijuana after developing lupus and later multiple sclerosis. “It’s more private.”

Whether delivery services are legal is another question.

As far as police, city officials and prosecutors from Santa Clara and San Mateo counties are concerned, delivering marijuana, even if it is medical, is illegal in most cases.

The Santa Clara County District Attorney’s Office says there is just one exception. If a caregiver is responsible for a medical marijuana user too sick to pick up cannabis, the caregiver can transport the marijuana. All other instances would be governed by state drug laws, which make it a crime to transport marijuana.

No one in either county has been arrested while delivering medical marijuana or prosecuted for it, officials said.

“We’re not out there to get individuals or collectives operating in the spirit of the law. We’ve got bigger fish to fry,” said Alcantara, who added that though it is not now a priority to bust delivery services, enforcement could start at any time.

San Mateo County prohibits delivery, with a few exceptions. For example, a medical marijuana dispensary that has been licensed by the county can deliver in unincorporated areas. But none have gotten the county’s stamp of approval since the ordinance was passed last spring.

In fact, the San Mateo County Sheriff’s Office sent a letter to Green Access in February warning that “the distribution of marijuana is illegal, subject only to the narrow state law exception for collective cultivation of marijuana.”

Fallah’s attorney, Scot Candell, sent a letter in response, and no action has been taken since.

Candell said cities can prohibit dispensaries from setting up in their jurisdiction using zoning rules, but they can’t stop a delivery service from driving into their towns.

“They don’t have the authority to say what is traveled on their streets and brought to somebody,” he added.

Hermes said a delivery service is essentially a mobile medical marijuana collective, and collectives are allowed under California law. He added that people who are too sick to drive to a dispensary have no other way of getting their marijuana.

But the legal debate over medical marijuana and delivery services might be rendered moot come November, said Mayer. Voters will decide whether they want to make marijuana legal for personal use.

“It passes, and we don’t have these discussions anymore,” he added.