Welcome to the Composting FAQ

Composting is a powerful way to reduce waste, protect our environment and support local food systems. But it only works when we all follow a few simple rules. Our region’s only commercial compost manufacturer, A1 Organics, changed what materials they accept from communities along the Front Range. These changes are in response to the high levels of contamination in compost streams. By composting the right way, we can keep contamination out of the bin, create clean, usable compost and help nourish healthy soils that grow fresh, local food for our community.

Explore the FAQs below to learn how to compost correctly—and why it matters.

Only compost:

  • Food scraps
    • Including meat, bones, dairy, coffee grounds and eggshells.

  • Plant and yard trimmings
    • Leaves, twigs, flowers, grass and other lawn trimmings.

If it was on your plate or grew in your lawn, put it in the compost bin. Please place materials loosely in your bin.

Compost food scraps, grass clippings, leaves, flowers and other yard trimmings.

Have questions? Here are some answers! 

If it isn’t food scraps, yard or plant trimmings, it doesn’t go in the compost bin.

Keep these out of your compost bin – they belong in the trash:

  • All compostable packaging and products, including certified compostable utensils, cups, plates and to-go containers. Please do not put cups in the recycling stream. Disposable plastic and compostable cups are not recyclable.
  • Paper products, like towels, napkins and shredded paper.
  • Pizza boxes. Please throw away the greasy half of the box and recycle the clean half.
  • Coffee filters and tea bags. Dump coffee grounds and tea leaves into your compost bin and trash the filter or bag.
  • Most bags are not allowed, including large certified compostable bags used to line bins. Keep plastic bags out. Check out A1 Organics' website for a list of allowed compostable bags.

What about lawn and leaf bags?

Many waste haulers are still collecting large, brown paper bags used for yard trimmings. These bags must be left next to your compost bin. Please check with your waste hauler for more information. Large yard trimmings, like branches, can be taken to Western Disposal’s Yard Waste Drop-Off Center for a reduced fee.

Got bag questions? Reach out to your waste hauler for more information.

Compostable bags often contain and conceal contamination. Help A1 and your waste hauler make sure your compost is free of contaminants by skipping compostable bags.

Note that there are two exceptions to the no bag rule:

  1. You are allowed to use small CMA-approved compostable bags. Bags must be three gallons or smaller. Check out A1 Organics' website for a list of accepted bags.
  2. Many waste haulers are still collecting large, brown paper bags used for yard trimmings. These bags must be left next to your compost bin. Please check with your waste hauler for more information.

The city recognizes that changes in accepted materials for compost collection by A1 Organics are causing problems related to compliance with the existing Universal Zero Waste Ordinance requirements outlined in Boulder Revised Code 6-3-13, 6-3-14, and 6-3-15. The City of Boulder is currently collaborating with regional partners on potential solutions. For now, the city will pause enforcement of compost requirements in these code sections until further notice. Commercial and multifamily complex properties, along with special events, will not be penalized for discontinuing compost collection services.

  • Remove compost bins from customer spaces.
  • Communicate these changes to staff and include compost guidelines in all new employee orientations. The city has a Waste Sorting 101 web guide and sorting game to help staff learn the basics.

Find more waste sorting resources on the city’s Universal Zero Waste Ordinance webpage.

Yes! All restaurants create large amounts of food waste and the city’s compost collection requirement for food businesses remains in effect. The only sure way to divert food scraps from the landfill is to have kitchen staff collect them in food prep areas and bussing staff sort what they clear off customer tables.

Continue to use your compostable products but tell customers and employees to put these products in the trash. We understand that this contradicts prior guidance and may not feel good, but this must be done to ensure your compost doesn’t end up in the landfill. If you have unopened cases of compostable products, you may be able to return them to the vendor who sold them to you.

Go bag free and simply rinse out your indoor compost container. If it gets stinky, give it a quick rinse from the hose, swish it around and pour the water directly onto your lawn or trees. You can also line your compost bin with a thin layer of grass or leaves to help absorb moisture.

Help protect our waterways by not dumping water with food and soap residue into the street. Storm drains in our community lead directly to local creeks.

There are multiple reasons.

  • For every certified compostable product, there are several more look-alikes that seem compostable. In truth, they often contain harmful plastics.
  • Unfortunately, the volume of contamination A1 receives due to misleading labeling and non-compostable look-alikes makes any packaging or product too costly to accept.
  • The same is true for paper. Many paper to-go containers are coated in plastic. This coating leads to microplastics in compost.
  • Compostable bags often contain and conceal contamination.

Please note: Paper that has no plastic coating, like paper towels, facial tissues (that are not synthetic) and coffee filters are compostable in your backyard compost. Learn more about backyard composting!

No, compostable products are not recyclable. Please put them in the trash.

Boulder’s circular economy goals include reusing items as much as possible.
The city has an incentive of up to $2,000 per business to support reusable systems and dining items. Visit Partners for A Clean Environment for more information.

If you have dishwashing facilities, switch to reusables.

  • Stock your break room with reusable mugs, plates, forks and spoons. On a tight budget? Many thrift stores have affordable, reusable cutlery and tableware for sale.

No dishwasher?

  • Switch to reusables! Sign up for a local reusable service. These companies make it easy to choose reusable containers while saving you money on single-use packaging.
  • r.world provides reusable cups to entertainment venues and events.
  • Provide disposables to customers by request only. If your business uses an online ordering platform, create an opt-in checkbox for single-use items.
  • Create a reuse culture in your workplace by encouraging employees to pack their own reusable utensils, cups and napkins for lunch in and out.
  • Use recyclable containers as a last resort. Be sure to check the city’s 

Waste Sorting 101 guide to see which to-go containers are recyclable.

Have questions about reusables?

Reach out to Partners for A Clean Environment by emailing info@PACEpartners.com or calling 303-786-7223.

  • Use unlined, small containers that staff can carry to compost carts and dumpsters. Any bucket will work well to collect food scraps.
  • Line larger compost containers with bags and have staff remove them after dumping contents loose into a cart or dumpster. Reuse bags for as long as possible. When they can no longer be used, put them in the trash.

  • Keep your bins out of direct sunlight.
  • Use local cart washing services. Your hauler may offer one.
  • Increase waste hauling service frequency.

Contact your hauler; they can provide guidance.

Reach out to your waste hauler to request a locking bar or lid for your compost container. Also ask for additional resources, like signage.

Compostable products were not commonly used until relatively recently. As their popularity has grown, they have spurred a rush of look-alikes in the marketplace. While compostable bags and food containers can be useful, the task of identifying what is actually compostable is next to impossible.

Absolutely! Two of the of the most impactful ways to help are to:

  • Use reusables whenever possible.
  • Bring your reusable mug to a coffee shop.
  • Stash a set of reusable utensils in your bag or car for easy access on-the-go.
  • Know before you throw. Checking out our Waste Sorting 101 guide for more local waste sorting knowledge.

Reuse services and products are on the rise, so encourage your favorite restaurants and companies to ditch disposables and use reusables instead.

Plant and yard trimmings can always be put in your curbside compost cart. In Boulder, residential compost bins are bundled with your trash. So, if you’d like a larger compost cart, please check with your waste hauler.

Many waste haulers are still collecting large, brown paper bags used for yard trimmings. These bags must be left next to your compost cart. Please check with your waste hauler for more information.

Large yard trimmings, like branches, can also be taken to Western Disposal’s Yard Waste Drop-Off Center for a reduced fee.

Compost truck loads containing anything other than food scraps, plant and yard trimmings will be refused by the company and sent to the landfill.

Please contact your waste hauler for more information.

The compost stream is not the same as the recycling stream. At a recycling plant, human sorters see contaminants like plastic bags and pull them off the sorting line by hand. Automatic equipment like screens and optical sorters also help separate materials.

Compost is not so tolerant. By the time compostable materials arrive at a compost plant, they are already a gooey mess. Imagine pulling plastic stickers off rotten banana peels.

Compost is ground and processed through screens, but small pieces of plastic, glass or aluminum will remain in the finished compost product. Farmers and other compost buyers need clean, nutrient-rich food scraps and yard trimmings. They don’t want to grow our food using compost contaminated with glass, plastic and metals.

Many commercial compost manufacturers have simplified their guidelines because of contamination challenges and a rising demand for quality compost. This has impacted programs in other early adopter composting communities.

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