Where do you think that goes? Maybe not where you expect. It turns out, much of it ends up in landfills with all the garbage.
It's legal, but environmentalists believe it shouldn't be.
All over the Bay Area, residents are separating green waste from garbage. The cans go out, the trucks pick it up. But then what?
"I assumed that it would go to a recycling plant," said Diane.
"Hopefully it gets turned into mulch and used as a recycle," said one Bay Area resident.
Well, in some areas that is what happens. Green waste is composted and reborn a few months later as a nutrient rich product that's added to soil.
It's so good, Sonoma landscaper Maile Arnold says she doesn't even use fertilizer any more.
"I just keep adding the stuff to my pots and look at the results. It's just astonishing to me," said Arnold.
But statewide, most green waste never becomes compost. About half ends up at the dump.
And what makes environmentalists even angrier is that a quirk in state law still counts all that green waste toward California's recycling goals.
So, a truck load of green waste going into Fremont's tri-cities landfill will actually be counted by the state as material that was diverted "away" from the landfill.
If that doesn't make much sense to you, you're not alone.
Gordon Bennett is with the Sierra Club.
"It's a fraud. It may be legal, but it's a fraud. It is not being recycled, it's being land filled," said Gordon Bennett from the Sierra Club.
The reason landfills can count green waste as "diverted" is that they use it for what the state designates as "beneficial" purposes. Sometimes "beneficial" means putting it on the side slopes of a landfill as erosion control.
Landfills also use green waste to cover the garbage at night.
"If you don't cover it, you have noxious gas problems. You have vector problems, you have, I'm sorry that's fancy language, you've got stink and you've got rats," said Steve Glickman from West Valley Solid Waste Board.
So green waste, which can include yard clippings, branches or wood is spread over the trash. The next day - more garbage is piled on top.
Landfills are allowed to use a number of waste products to cover the garbage at night, things like construction and roofing debris, sewage sludge, or parts of demolished cars -- all things that can not generally be recycled. And the most common daily cover is plain old dirt.
Still, even with all those options, landfills use a lot of green waste as cover -- three million tons a year mixed with California garbage.
But why? Again, it's that quirk in California law. Remember: local governments get credit for keeping green waste out of the landfill even when they're putting it in.
"Under California waste reduction and recycling laws, local jurisdictions are responsible for diverting 50-percent of their waste from the landfill. Well this is a very cheap way to get that recycling or diversion credit," said Scott Smithline from Californians Against Waste.
It may be cheap, but it's not common. No other state in the nation does it this way. In fact, about half the states have banned green waste from their landfills altogether.
Environmentalists are demanding change, and the city of San Jose is on the front lines of that fight.
San Jose has signed contracts that prevent its haulers from taking its yard waste to a landfill. At least half must be composted, even if it costs more.
"Recycling is always more expensive than land filling, but we have built that into our contracts and our residents feel that it's very important that the material is used for a beneficial use for the environment," said Michele Young from San Jose Environmental Services.
San Jose yard waste is sent to Gilroy where it's turned into compost. The manager would love to get more green waste from other cities because he can't make enough compost to meet demand.
The problem is much of the yard waste is going to landfills instead.
"If we had an extra 50,000 tons of material right now, it would have been gone, it would have been sold," said Michael Gross from Z-Best Compost.
Waste Management which owns the tri-cities landfill in Fremont argues they also make good use of green waste. But it's not always easy to be sure.
This is what they told us.
"About 75 percent of the green waste that is brought into that facility is specifically brought in for erosion control," said Waste Management spokesperson Monica Devincenzi.
That may be true, but that's not what the Alameda County report to the state shows. In the column where green waste used for erosion control should be listed, there is nothing.
And then there's this truck driver-- who didn't want his identity revealed to protect his job. He claims on a number of occasions he brought yard waste to the tri-cities landfill and saw it treated like trash, not cover or erosion control.
"I saw too many times they push the yard waste over the garbage," said the driver.
ABC7's Dan Ashley: "Just into the landfill."
"Yes in the landfill," said the driver.
And while this driver seemed certain about what he saw, Waste Management suggests perhaps he misunderstood what was going on.
Either way, the company insists it's against policy to simply plow green waste into garbage.
ABC7's Dan Ashley: "So if that happened, it should not happen."
Monica: correct.
ABC7's Dan Ashley: "And it's not something that you guys would approve of, that management would approve of?"
Monica: "Absolutely not."
Whatever is happening to green waste at California landfills, it's clearly not what most Californians are expecting when they roll their yard waste down to the curb.
"People would assume if it's in a segregated can, it's for the purpose of composting, otherwise it would just be in the trash," said homeowner Diane Fisher.
Northern California is actually way ahead of Southern California in composting green waste. But many environmentalists believe the situation won't get much better until the law that gives cities recycling credit for sending green waste to the landfill is changed.
The California Integrated Waste Management Board will look into this issue next month. We'll let you know what happens.
Written and produced by Jennifer Olney.
