Seattle's Residential Composting Rules: Your Guide to Proper Disposal

Seattle is committed to sustainability, and its residential composting program is a cornerstone of this effort. By diverting organic waste from landfills, you help reduce greenhouse gas emissions and create nutrient-rich soil. Understanding and following Seattle Public Utilities (SPU) guidelines is essential for all residents to ensure the program’s success.

Seattle’s Residential Composting Program: An Overview

Seattle’s comprehensive residential composting program is designed to make it easy for homeowners, renters, and property managers to responsibly dispose of their organic waste. Participation helps Seattle achieve its environmental goals by reducing landfill waste and transforming food and yard scraps into valuable compost. The program is managed by Seattle Public Utilities (SPU) and serves as a vital part of the city’s waste management strategy, emphasizing ecological responsibility from every household.

Accepted Materials: What Goes in Your Compost Bin?

Knowing what to compost is the first step to successful participation. SPU has clear guidelines to prevent contamination and ensure the quality of the finished compost. Generally, if it grew, it goes!

Food Scraps:

  • All fruits and vegetables (raw, cooked, rotten)
  • Meat, poultry, and fish (cooked or raw, including bones)
  • Dairy products (yogurt, cheese, etc.)
  • Bread, pasta, grains, and baked goods
  • Eggshells
  • Coffee grounds, tea bags (staple-free)

Yard Waste:

  • Leaves, grass clippings, weeds
  • Small branches and twigs (up to 4 feet long and 4 inches in diameter)
  • Garden trimmings, plant material
  • Holiday greenery (wreaths, garlands – remove non-compostable decorations)

Approved Soiled Paper Products:

  • Paper towels and napkins (not saturated with chemicals)
  • Paper plates (not coated with plastic or wax)
  • Pizza boxes (greasy parts are fine)
  • Shredded paper (in a paper bag)

Prohibited Materials: What Must Stay Out to Avoid Contamination?

To maintain the integrity of the composting process and protect municipal composting facilities, certain items are strictly forbidden. Including these non-compostable materials can lead to your bin being rejected and disrupt the entire system.

Do NOT put the following in your compost bin:

  • Plastics of any kind: This includes plastic bags (even if labeled ‘biodegradable’ unless BPI-certified), plastic packaging, plastic cutlery, Styrofoam.
  • Glass and metal: Bottles, jars, cans, foil.
  • Pet waste: Animal feces, cat litter, dog waste bags.
  • Liquids: Large quantities of grease, oil, or other liquids.
  • Diapers: Soiled or otherwise.
  • Treated wood: Lumber, painted wood.
  • Ash: From fireplaces or BBQs.
  • Rocks, dirt, and sod: Compost bins are not for construction or landscaping debris.
  • Produce stickers, rubber bands, twist ties, bread tags: Small as they are, these contaminate compost.

Compost Bin Requirements and Approved Liners

SPU typically provides standardized compost bins to residents. For lining these bins, specific rules apply to ensure compatibility with the commercial composting process:

  • Approved Liners: You must use either BPI-certified compostable bags or plain paper bags/liners. Look for the BPI (Biodegradable Products Institute) certification logo, often found on the packaging of bags sold at grocery or hardware stores.
  • No Regular Plastic Bags: Do not use regular plastic grocery bags, even if they are marketed as ‘biodegradable’ or ‘degradable’ without the BPI certification. These materials do not break down in commercial composting facilities and are a major source of contamination.

Preparing Your Compostables and Collection Day Logistics

Proper preparation and placement are key to a smooth collection process:

  1. Drain Liquids: Scrape food scraps directly into your bin. If using a liner, ensure wet items are not excessively soupy.
  2. Cut Large Items: Break down large food items or bundle yard waste (branches up to 4 feet in length and 4 inches in diameter) so they fit easily into the bin.
  3. Secure Lids: Always ensure the lid of your compost bin is securely closed to prevent odors, pests, and spillage.
  4. Collection Day: Place your compost bin at the curb by 7 AM on your designated collection day. Your specific collection schedule can be found on the SPU website by entering your address.

Avoiding Contamination Penalties and Rejected Bins

SPU performs visual checks of compost bins. If contaminants are found, your bin may be tagged and left uncollected. Repeated contamination can lead to service changes or potential fines. To avoid these issues:

  • Educate Everyone: Make sure all members of your household understand the rules.
  • When in Doubt, Throw it Out (in Garbage): If you’re unsure if an item is compostable, it’s safer to place it in the regular garbage to avoid contaminating the compost stream.
  • Review Regularly: Periodically review SPU’s updated guidelines, as acceptable materials lists can sometimes change.

How to Verify in Seattle Today

For the most current and specific information regarding Seattle’s residential composting rules, use these practical verification steps:

  1. Visit the Official SPU Website: Go directly to www.seattle.gov/utilities/services/recycling-and-compost/compost. This is the primary source for all official guidelines, accepted materials, and program updates.
  2. Use SPU’s “What Do I Do With…?” Tool: On the SPU website, look for their interactive tool where you can type in specific items and get immediate guidance on whether they belong in compost, recycling, or garbage.
  3. Contact SPU Customer Service: For questions about unique items, missed collections, or specific service inquiries, call Seattle Public Utilities customer service. Their contact information is readily available on their website.

Your Decision Checklist for Composting in Seattle

Use this quick checklist before placing your compost bin out for collection:

  • Have I separated all food scraps from non-compostable packaging (e.g., plastic wrap, stickers, metal clips)?
  • Is my compost bin free of any plastic bags, glass, metal, Styrofoam, or pet waste?
  • Am I using a BPI-certified compostable bag, or plain paper, and NOT a regular plastic grocery bag?
  • Is all yard waste trimmed to the correct length (max 4 feet) and bundled if necessary?
  • Is the lid of my compost bin securely closed and the bin placed correctly for collection?
  • Do I know my specific SPU collection day and have I placed my bin out by 7 AM?

Common Composting Mistakes to Avoid

Even with good intentions, some common errors can lead to contamination. Be mindful of these to ensure your composting efforts are effective:

  • Using regular plastic grocery bags or uncertified ‘biodegradable’ plastics in the compost bin.
  • Including pet waste, animal litter, or animal carcasses, which are strictly prohibited.
  • Placing produce stickers, twist ties, or plastic bread tags onto otherwise compostable food scraps.
  • Overfilling the compost bin, preventing the lid from closing securely and leading to spillage or non-collection.
  • Putting large branches or stumps that exceed SPU’s size limits for yard waste.
  • Assuming all ‘compostable’ packaging is accepted; only BPI-certified items (if approved by SPU) or plain paper are typically allowed.

Troubleshooting Common Composting Issues and Resources

Occasionally, you might encounter issues with your composting. Here are some common problems and solutions:

  • Odors: Secure the lid tightly. Try layering food scraps with some yard waste or shredded paper. Ensure wet items are drained before placing them in the bin.
  • Pests: A tightly sealed lid is your best defense. Consider placing the bin in a shaded area if possible. Regular collection helps prevent pests.
  • Missed Collection: If your bin wasn’t collected, first re-check your collection day and ensure it was out by 7 AM. Then, verify there were no contamination tags. If all seems correct, contact SPU customer service directly to report the missed pickup.

For further assistance, updated schedules, or to report issues, always refer to the official Seattle Public Utilities website or contact their customer service line.

Frequently Asked Questions about Seattle Composting

Q: Do I need special bags for my compost bin?

A: Yes, you must use BPI-certified compostable bags or plain paper liners. Regular plastic bags, even those labeled ‘biodegradable’ without BPI certification, are NOT allowed.

Q: Can I compost all packaging labeled ‘compostable’?

A: Not necessarily. Only BPI-certified packaging, specifically if approved by SPU, is generally accepted. It’s best to stick to natural materials like food and yard waste, and only BPI-certified bags. When in doubt, err on the side of caution and place it in the garbage.

Q: What should I do if my compost bin is rejected?

A: If your bin is tagged and not collected due to contamination, remove the prohibited items. The bin will then be eligible for collection on your next scheduled service day.

Q: Is pet waste allowed in the compost bin?

A: No, pet waste (including animal feces and cat litter) is strictly prohibited from the residential compost program due to potential health concerns and processing limitations.

Q: Where can I find my specific compost collection schedule?

A: You can find your collection schedule by visiting the Seattle Public Utilities website and entering your residential address into their service lookup tool.