Neighbors never saw much activity around the house at 2171 Tennis Lane until federal drug agents showed up Friday afternoon.

Most likely, it was the quiet anonymity of a new subdivision that appealed to the Bay Area drug ring that established this as one of many marijuana “grow houses” in the Central Valley.

Friday’s raid, which also included six houses in Lathrop and netted nearly 5,000 plants, brings the count of Central Valley houses raided since August by federal agents and local police to 48.

Gordon Taylor, special agent for the Drug Enforcement Administration, said it was a small raid compared with the seizure of plants at 21 houses in Sacramento County in August and raids on 20 houses in Stockton in September.

But it was the biggest raid so far in terms of arrests. The DEA and local police served search warrants for a house in Oakland and two more in San Francisco, where they arrested seven people. They arrested another person at one of the Lathrop houses. Agents found no one at the Tracy house. All of the people arrested are from Oakland, San Francisco or other Bay Area cities.

People who live near the house on Tennis Lane said they never saw suspicious activity.

“We never saw anyone, really,” said the next door neighbor, who did not give her name. “A lot of these homes, you never see anyone go in and out.”

It’s a clean two-story stucco house with a neatly trimmed front lawn. The house next door has a real estate agent’s key box hanging on the front door, as does the house across the street. Another nearby house has tumbleweeds accumulating in the driveway.

The neighborhood is about two years old.

Elena Costa, who lives a couple of houses away, said the most activity she had seen was on Friday afternoon, when people wearing police and federal DEA jackets showed up.

“As far as I knew, the house was empty,” she said.

That activity prompted another neighbor to call police at about 6 p.m. Friday and report four moving vans at the house and several people with flashlights, and the obvious smell of marijuana.

The smell would have come from the 575 plants that DEA agents seized at the house, and the vans were needed to haul away the plants and the indoor growing equipment.

Taylor said it is typical for these grow houses to be vacant except for plants and greenhouse equipment.

“It was purely used for growing,” he said. “They were using virtually every room in the house for cultivation or to store equipment for the cultivation business.”

In all, agents seized 4,931 plants. Taylor said just these seven grow houses could produce about 5,000 pounds of marijuana, worth about $20 million, every year. They also found 10 pounds of marijuana ready for sale at one of the San Francisco houses along with nearly 500 Ecstasy pills and a TEC-9 assault pistol at the Oakland house. Agents also seized about $63,000 in cash.

To reach reporter Bob Brownne, call 830-4227 or e-mail brownne@tracypress.com.