ENCINITAS - Federal authorities seized 440 marijuana plants, arrested three people and confiscated two vehicles Tuesday in a raid of residential marijuana growing operations at multiple residences across San Diego County, Drug Enforcement Administration spokeswoman Eileen Zeidler said.

Zeidler declined to specify the locations or suspects, citing the ongoing investigation. One of the raids occurred in Encinitas at 305 Camino de las Flores, part of a well-kept middle-class neighborhood.

At least a dozen law-enforcement officials were collecting evidence at the house Tuesday morning and early afternoon. A neighbor reported seeing agents carrying out about 100 plants in the early morning. Two BMW automobiles parked in the driveway were later towed.

Plainclothes federal agents, aided by San Diego County Sheriff's deputies, also seized a wide assortment of materials commonly associated with marijuana growth: blue one-gallon buckets, ventilation and odor-reduction equipment, growing lights, industrial fans and pumps. They stacked the materials in a panel truck, nearly filling it.

Zeidler said the DEA's Narcotics Task Force, a multiagency law enforcement effort with two units in North County, coordinated the raids. They obtained sealed search warrants for the properties, although Zeidler didn't say where or when the warrants were obtained.

The suspects arrested face state charges of possession and cultivation of marijuana and theft of services for allegedly stealing electricity and gas required to operate the grow houses, Zeidler said.

She said more arrests are expected, but did not specify details.

So-called hydroponic marijuana, grown inside, typically has a much higher street value than outdoor plants, Zeidler said, because growers can control temperature, lighting and moisture levels. A pound of marijuana grown indoors fetches about $3,000 to $4,500 depending on the plant, she said.

Raids on indoor grow sites are not uncommon. Last year, federal agents raided 66 indoor grow houses countywide, up slightly from 59 in 2006, Zeidler said. Although Tuesday's raids were larger than most, Zeidler said she "didn't think it was going to be record-breaking" in total plants seized.

As agents carried out the growing materials Tuesday morning, a neighbor cradling a white dog in his arms approached the agents and thanked them, saying he was glad to see his tax dollars at work.

Contact staff writer Dan Simmons at (760) 740-5426 or dsimmons@nctimes.com.