It’s easy for politicians to set goals for their cities. It’s far, far harder to achieve them.

Take San Francisco’s much-heralded goal of sending absolutely no garbage to landfills by the year 2020. In a composted nutshell? It’s nowhere near happening.

Back in 2003 when the city’s Commission on the Environment, at the urging of Mayor Willie Brown and the entire Board of Supervisors, set that goal, it was considered achievable.

But 13 years later, and just four years from the goal date, San Francisco continues to throw away huge amounts of garbage. The city’s waste has averaged 1,463 tons every workday over the past year, according to Recology, the city’s trash collector. There’s no penalty for not meeting the target other than, of course, a swelling landfill that’s bad for the environment and a big dent in San Francisco’s reputation as one of the greenest cities in the world.

“We haven’t hit our targets,” said Guillermo Rodriguez, spokesman for the Department of the Environment. He called the zero waste plan a “big, audacious goal” that the city is still trying to meet, but admitted not everybody is doing their part.

“Really, we need our businesses and residents to do a much better job,” he said, pointing out that 50 percent of what San Franciscans put in their black bins could be recycled or composted instead.

Recology began keeping daily garbage averages in 2008, but the annual trash tallies kept dating back to 2000 show big strides followed by complacency. In 2003, the year the zero waste goal was set, 581,567 tons of waste were sent to the city’s landfill, 148,000 fewer tons than in the year 2000. Last year, that figure had dropped to 386,854, a 33 percent decrease. The lowest tally came in 2012 when 366,504 tons of trash went to the landfill, but that figure has crept up every year since.

Like so much else in San Francisco, trash heaps grow and shrink along with the economy. More residents, more workers and far more construction projects mean more garbage, despite whatever goal was set all those years ago.

Every workday, garbage trucks trundle into Recology’s Transfer Station — better known as the dump — on Tunnel Avenue and unload their collected trash into a cavernous space twice the size of a basketball court and measuring 20 feet deep. An average day sees the gigantic hole filled 10 feet deep, a busy day even more.

“Welcome to the pit,” said Recology spokesman Robert Reed on a recent visit to the pungent site. The clinking noise coming from unloading trucks signaled city residents had put a lot of recyclable glass into their black bins. The aroma signaled plenty of compostable food was in there too. None of that can be plucked from the heap, and it all winds up in the landfill.

“This is the sad place — it should be empty,” Rodriguez said as he surveyed the huge pile of garbage. “This is where we need residents to do a better job.”

San Francisco has a reputation for being hugely environmentally friendly. In 2002, the Board of Supervisors unanimously approved a long-term goal of producing zero waste and rolled out what the city dubbed the “fantastic three” — the blue, green and black bins that have become so well known. The next year, the Commission on the Environment specified the long-term goal for producing no trash would be 2020.

Since then, the city has continued to be on the cutting edge of environmental initiatives. It banned plastic bags in 2007. It mandated composting in 2009, telling residents they had to place food waste in their green bins or risk being fined. It implemented the strictest ban on Styrofoam in the nation in June.

But that environmental ethic doesn’t always translate to what city residents and workers place in their bins. In fact, San Franciscans create more trash every day than they do recycling and composted material together. Those clock in at about 600 tons and 650 tons a day, respectively.

Reed said San Francisco is probably the only city in the country that composts more than it recycles, and that’s a good thing because composted material is so valuable. Not only can Recology sell composted material for use in farming, but keeping food waste out of blue bins means the recycled paper is also cleaner and can be sold for more money.

Still, Reed said, San Franciscans can do a better job at composting. Some tips? Empty that old bag of bread or jar of spaghetti sauce into the compost bin before discarding the packaging. During refrigerator clean-outs, save all the waste, like soggy bits of vegetables at the bottom of the produce drawer and compost them.

Restaurant workers, Reed said, are placing far too much recyclable material, like bottles and jars, into green bins, apparently by mistake at the end of a busy shift. Many of their plastic gloves are found in the green bins, too.

Recology is working to do its part to get closer to that elusive zero waste goal. Its recycling facility is undergoing a $12 million upgrade, which should be completed in November and will enable more material from blue bins to be recycled.

Reed said it’s also important for shoppers to consider what they buy in the hope of swaying manufacturers to produce less packaging. For example, he said, buy bread in a paper sleeve rather than a plastic bag. Currently, soft plastics of any kind — such as bread bags — can’t be recycled by Recology and go to the landfill.

A tour of Recology’s separate recycling facility at Pier 96 in Hunters Point made it clear how confused residents are about what goes in the blue bins and how much excess packaging is produced by manufacturers.

Like Willy Wonka’s chocolate factory but for garbage, the facility’s conveyor belts and other gadgetry whisk discarded junk through the huge hangar as scores of staffers standing on different levels pluck items that can’t be recycled from the piles.

“We see things like frying pans, tennis shoes, VCR tapes, garden hoses,” Reed said. “You see everything.”

(During the “Sex and the City” craze in the early 2000s, Christmastime brought the distinct smell of vodka to the facility because, Reed said, every other woman in San Francisco was ordering a cosmopolitan at her holiday party. That meant lots of vodka bottles in the blue bins. Now, the facility is back to smelling like wine in December.)

A look at all those items whirring around the facility shows huge numbers of plastic water bottles, plastic containers that once held fruit or other food, and plastic bags of all sorts. The latter get wrapped around the machinery, gumming it up. As online shopping gets more popular, enormous amounts of cardboard and bubble wrap make their way to the center.

Darryl Moses, the recycling center’s operations manager, said he thinks Recology does a good job of outreach and education when it comes to letting people how to sort trash and how to reduce the amount of junk produced.

“We let you know what you should put where and what you shouldn’t,” he said. “If people would follow that, it would help take us a long way.”

But if the city doesn’t turn it around quickly and the zero waste goal is not met, then what?

“It’s still a goal that we’re shooting for,” Rodriguez said. “Is anything less than zero a success? I don’t think we’ve had that conversation.”

Heather Knight is a San Francisco Chronicle staff writer who covers City Hall politics. Email: hknight@sfchronicle.com Twitter: @hknightsf