Seattle Residential Food Waste Composting: Rules, Accepted Materials, and Collection

Seattle Composting Program Basics

Seattle is committed to sustainability, and its mandatory residential food and yard waste composting program is a cornerstone of this effort. All residents with garbage service in Seattle are required to separate their food scraps and yard waste for composting. This initiative helps divert valuable organic materials from landfills, reducing greenhouse gas emissions and producing nutrient-rich compost for local use. Understanding the rules ensures your participation is effective and contributes to a healthier environment.

Accepted Materials: The ‘Yes’ List

To successfully compost in Seattle, it’s crucial to know what items belong in your green cart. Seattle Public Utilities (SPU) maintains a clear list of accepted materials:

  • All Food Scraps: This includes cooked and uncooked food, meat, bones, poultry, fish, dairy products, eggs and eggshells, bread, pasta, fruits, vegetables, and coffee grounds (with filters).
  • Food-Soiled Paper Products: Items like pizza boxes (without excessive grease or plastic liners), paper towels, paper napkins, coffee filters, tea bags, and paper bags used for collecting food scraps. Crucially, these must be food-soiled, not merely clean paper.
  • Yard Waste: Grass clippings, leaves, weeds, brush, small branches (no more than 4 feet long and 4 inches in diameter), and untreated wood scraps.
  • BPI-Certified Compostable Products: Only items specifically labeled as BPI-certified compostable (e.g., cups, plates, cutlery, bags). Look for the BPI (Biodegradable Products Institute) certification logo.

Prohibited Materials: The ‘No’ List

Contamination is the biggest challenge for composting programs. Placing incorrect items in your green cart can lead to rejected collections and harm the composting process. Here’s what absolutely does not belong:

  • Plastics: Any plastic bags (including those labeled “biodegradable” unless they are BPI-certified compostable), plastic wrap, plastic containers, or Styrofoam.
  • Glass, Metal, and Electronics: These materials do not break down and can damage composting equipment.
  • Pet Waste and Animal Carcasses: This includes dog and cat waste, kitty litter, and any dead animals. These items can contain pathogens harmful to human health and are not suitable for composting facilities.
  • Diapers and Sanitary Products: These are non-compostable and can carry harmful bacteria.
  • Treated Wood: Wood that has been painted, stained, or pressure-treated contains chemicals that are toxic to compost.
  • Hazardous Waste: Batteries, chemicals, medical waste, and other hazardous materials must be disposed of through specialized programs, not in the compost.

Preparing Your Compostables & Cart

Proper preparation helps keep your cart clean, minimizes odors, and ensures successful collection.

Inside Your Home

Collect your food scraps in a countertop container, an old coffee can, or a small paper bag. When it’s time to transfer to the green cart:

  • Use BPI-Certified Bags (Optional): If you choose to bag your food scraps, use only BPI-certified compostable bags. Regular plastic bags are never allowed.
  • Wrap Wet Scraps: For very wet items, wrap them in newspaper or a paper towel before placing them in the cart to absorb moisture and prevent sticking.

Preparing Your Green Cart

  • Lining the Bottom: Consider lining the bottom of your cart with a layer of newspaper or yard waste to prevent food scraps from sticking.
  • No Plastic Bags: Again, emphasize this: no plastic grocery bags, produce bags, or garbage bags in the green cart.
  • Odor Control: Keep the lid tightly closed between collections. You can sprinkle baking soda or a thin layer of yard waste on top of food scraps to help absorb odors. Freezing particularly odorous scraps (like meat or fish) until collection day can also help.

Collection Details & Service Management

Collection Schedule & Cart Placement

Residential food and yard waste is collected weekly in Seattle. To ensure your cart is serviced:

  • Placement: Place your green cart at the curb or alley by 7 AM on your designated collection day.
  • Clearance: Ensure there is at least three feet of clearance around the cart from other objects (like cars, mailboxes, or other bins) to allow collection trucks easy access.
  • Lid Closed: The lid must be completely closed. Overfilled carts may not be collected.

Cart Sizing & Service Changes

Seattle Public Utilities offers various green cart sizes (e.g., 13-gallon, 32-gallon, 64-gallon, 96-gallon) to suit different household needs. You can request to change your cart size by contacting SPU. For missed collections or inquiries about holiday schedules, check the SPU website or contact their customer service directly. Holiday schedules often result in a one-day delay for collection.

Avoiding Contamination & Fees

Preventing contamination is paramount for the success and efficiency of Seattle’s composting program. Failure to comply can lead to consequences.

Common Composting Mistakes to Avoid

  • Placing compostable materials in plastic bags inside the green cart, leading to contamination and rejection.
  • Including pet waste, kitty litter, or animal carcasses in the compost, which are strictly prohibited due to health and processing issues.
  • Mistaking ‘biodegradable’ or ‘compostable’ labels on non-certified products as suitable for the green cart.
  • Mixing food waste with recyclables or general garbage, leading to rejected carts and potential contamination fees.
  • Not lining the cart bottom or wrapping wet food scraps, causing odors, pests, and material sticking to the cart.
  • Overfilling the cart or placing it incorrectly for collection (e.g., too close to obstacles), resulting in missed pickups or material spillage.

Consequences of Contamination

If your green cart contains prohibited items, SPU collectors may leave an orange tag warning you about the contamination. Repeated contamination can lead to your cart being rejected for collection, and in some cases, additional contamination fees may be applied to your utility bill. Correctly sorting your waste helps avoid these issues and keeps your service running smoothly.

Your Decision Checklist for Composting Success

Before placing items in your green cart, run through this quick checklist:

  • Have I checked if this item is on Seattle Public Utilities’ official ‘Accepted Materials’ list?
  • Is my compost material free of any plastic, metal, glass, or pet waste?
  • Am I placing compost directly into the green cart or using only BPI-certified compostable bags, never plastic bags?
  • Is my green cart placed at the curb by 7 AM on my collection day, with adequate clearance?
  • Have I secured my green cart lid to prevent pests and odors between collections?
  • Do I know the specific collection schedule for my address and any holiday adjustments?

How to Verify in Seattle Today

To ensure you have the most up-to-date information on Seattle’s composting rules and your specific service, here are practical verification steps:

  1. Visit Seattle Public Utilities’ Official Website: Navigate to the ‘Food & Yard Waste’ section on the Seattle Public Utilities (SPU) website. This is the primary and most reliable source for current rules, accepted materials lists, and service updates. You can often find a tool to look up your collection day by address.
  2. Contact SPU Customer Service: If you have specific questions about unusual items, cart sizes, or missed collections, call SPU’s customer service line. Their representatives can provide personalized guidance and confirm details relevant to your residential service.
  3. Check Your Utility Bill or Welcome Packet: Residential utility bills from SPU often include information or direct links to waste management resources. New residents might also receive a welcome packet with essential composting guidelines.

Frequently Asked Questions About Seattle Composting

Q: Can I use “biodegradable” bags for food scraps in my green cart?

A: No, generally not. Only bags specifically labeled as BPI-certified compostable are accepted in Seattle’s green carts. Many products labeled “biodegradable” do not break down in commercial composting facilities and are considered contaminants.

Q: What if I have pet waste from my cat or dog?

A: Pet waste, including cat litter and dog feces, is strictly prohibited from Seattle’s green carts due to potential pathogens. It should be bagged and placed in your general garbage bin.

Q: How do I get a new or different sized green cart?

A: You can request a new or different sized green cart by contacting Seattle Public Utilities customer service. Fees may apply for cart exchanges or additional carts.

Q: What should I do if my collection was missed?

A: If your green cart was placed out correctly and on time but was missed, contact Seattle Public Utilities within one business day of your scheduled collection. They will investigate and reschedule your pickup.