A pilot program to beat back the scourge of illegal dumping is starting to see success on the streets of Oakland, where piles of discarded mattresses, couches and garbage have multiplied in recent years, according to city data.

Until about 10 months ago, pickup crews mostly relied on a complaint-based system in which they would clean an area when someone opened a service request. Now, the city Public Works Department also is proactively sending Garbage Blitz teams to sweep neighborhoods, moving block by block to pick up litter before it’s called in.

The work is slower, and it can take weeks for crews to move through an entire district. But city officials say the program appears to be deterring people from dumping in the first place.

“We’re out there cleaning more often. We’re turning illegal dumping hot spots to clean spots,” said Jason Mitchell, the public works director. “People feel more comfortable dumping on dirty streets than clean streets.”

The move comes as the city prepares to bring back its litter enforcement officers, who were eliminated during budget cuts in 2010.

In three zones of East and West Oakland where the neighborhood sweep program was piloted, the amount of trash that crews had to haul away on a daily basis declined each month they were there, according to data reviewed by The Chronicle.

In District Six of East Oakland, crews encountered a daily average of 8,600 pounds of trash in March. By May, the number dipped to 5,400.

Results were fruitful in other neighborhoods. In another zone of East Oakland, trash was cut from 4,800 pounds daily in September to 4,600 in October. In West Oakland, crews went from hauling away 6,600 pounds of trash daily in June to 5,800 by August.

Crews were logging the same or higher mileage. There was just less stuff for them to pick up.

A few technological fixes may have improved efficiency, too, Mitchell said. This time last year, public works trucks had to wait in line at a waste transfer station like any other citizen vehicle. Now, the city trucks are outfitted with the same electronic sensors as those belonging to Waste Management, the city contractor that hauls residential garbage.

“We’re able to get in and out of the dump in 15 minutes, whereas before it may have taken a little longer,” Mitchell said.

Public works will expand the proactive pilot program into every neighborhood of the city in coming weeks, although it won’t supplant the old system. City officials expect to have 25 employees continuing to do “eradication” work — responding to complaints — and 11 others on the new Garbage Blitz team. Those two divisions are on top of eight employees who exclusively clean homeless encampments.

“If we go fully proactive, it could take a week or two to get to a location,” Mitchell said. “If we know a pile exists, we don’t want it sitting there that long.”

The hybrid system brings Oakland more in line with San Francisco, which has regular street cleaning crews that pick up illegal dumping as well as crews assigned to hot spots. Like Oakland, San Francisco also has a complaint-based side and a team dedicated to homeless encampment cleans.

In addition to proactive pickups, Oakland is now holding “bulky block parties” once a month for residents to drop off tires, electronic waste, mattresses and other items for free. They’ve increased in popularity since they began in August, with more cars dropping off more junk as word has spread, city data show.

Educating the community on how to dispose of waste properly and levying citations on perpetrators is just as important as getting rid of trash on the streets, Mitchell said. The education component is key, he said, because much of the dumping comes from Oakland residents.

A 2017 study found that 55 percent of material in piles was residential waste — things like food, furniture and household appliances.

The city of origin of 63 percent of trash couldn’t be identified. But of the portion that could be traced geographically, more than three-quarters came from within Oakland.

Mayor Libby Schaaf said the issue makes her angry. Behavior and norms have to change for illegal dumping to end, Schaaf said.

“I personally find it outrageous that anyone could possibly think it’s appropriate to put their garbage in someone else’s neighborhood,” she said. “It is offensive, and it is an insult to the good families that live in these neighborhoods.”

The overall amount of dumping in Oakland is on the rise. In the 2012-13 fiscal year, crews had 17,870 pickups, or 49 a day. That number has grown steadily each year, and by 2016-17 it was 32,996, or 90 pickups a day.

Catching perpetrators is difficult. Since 2013, the city has issued 296 citations for illegal dumping, according to Greg Minor, whose office handles nuisance abatement.

What’s driving the increase is not clear. Mitchell and Schaaf said it could be partly Waste Management increasing its residential garbage fees.

Other factors could be the growth of the city’s overall population and the number of homeless encampments, Mitchell said.

Another reason, he said, could be that just before the recent uptick, the city had eliminated its litter enforcement officers. Now the city is rebooting the program and hiring four officers and a supervisor. The workers are expected to act as trash detectives — going through piles and video surveillance footage to track perpetrators.

Illegal dumping is concentrated in the poorer flatlands of the city, particularly in East Oakland, city data show. Many community members and organizations have said the reactive-versus-proactive cleaning approach was an issue of racial equity. Those most affected by dumping on their streets might not have the means to open service requests or know how to do it.

The sheer volume of trash on the streets has led some, like East Oakland resident Mary Forte, to pick up garbage on their own.

“It just gives you a feeling that people don’t care about East Oakland and where they live. They have no pride in the city that they would do things like this, and they’ll do it in certain neighborhoods but not others,” Forte said. “They wouldn’t dump it right in front of their own house, so why would they do it in other people’s neighborhoods?”

Forte, a 69-year-old retiree who is active in the East Oakland Congress of Neighborhoods and other volunteer organizations, has adopted her own spot through a city program that encourages residents to regularly clean a particular public space.

Forte applauded the expansion of the new proactive pickups but said the pace of hiring new workers has been too slow.

Mitchell said he understood the frustration of community members.

“It’s just bad to live in a neighborhood or go to school or go to my market with a pile of trash there,” he said. “Eventually, we want to get to the beautification of Oakland, where you see our workers, instead of cleaning up piles of debris, they’re planting flowers and putting in flower beds and beautifying neighborhoods.”

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov