Compost and Mulch Rebate

To encourage the use of compost and mulch, and to help meet statewide climate action goals, Zero Waste Sonoma (ZWS) is offering a 10% rebate for compost and mulch purchases totaling at least 30 cubic yards in ZWS's fiscal year (Jul 1 - June 30), up to $25,000. Compost and mulch greatly help to increase carbon sequestration, water retention, and the population of beneficial microbes in soil. In order to receive the rebate, please sign a short agreement consenting to the terms below.

Click to read and sign the agreement

Terms and Conditions

  • Only purchases made on the same day or after the agreement is signed are eligible for rebate.
  • Agreement shall expire at the end of ZWS's fiscal year (July 1 - June 30) and may be renewed on an annual basis.
  • Rebate is available for purchases totaling at least 30 cubic yards within ZWS's fiscal year. For example, if you purchase 20 cubic yards of compost and 10 cubic yards of mulch in one year, the two receipts can be submitted together because they total more than 30 cubic yards.
  • The total amount of rebate shall be capped at $25,000 within ZWS's fiscal year for each applicant ("Provider" in the Agreement)
  • Compost and mulch must be spread in Sonoma County.
  • Compost and mulch must be purchased from an authorized compostable material handling facility (see more info below).
  • Proof of purchase must list the name of compost facility, date of purchase, and quantity (in cubic yards) purchased.
  • A copy of most recent W-9 required for payment.
  • Rebate may be claimed for the cost of compost only.
  • Compost derivatives (e.g., compost tea, potting mixes, and soil blends) are not eligible.
  • Costs outside of purchase (e.g., transportation and spreading) are not eligible.

Approved facilities

Compost and mulch shall be eligible for rebate only if purchased from a compostable material or green material handling operation or facility in California. Nearby local facilities include:

Farther facilities are also acceptable and may be identified using the state's Solid Waste Information System (SWIS) database using the following link. Under "Activities", the facility should list "compostable material handling operation" or "green material handling operation".

Please note that the compost and mulch purchased must be spread within Sonoma County to be eligible for rebate. This ensures that the carbon sequestration benefits our soils and local communities.

Purchasing compost or mulch from a distributor and not directly from a compost facility? If the compost originates from an approved and permitted facility, as detailed above, the purchase will likely still qualify for rebate. Email if you're unsure.

Submit a Claim

Please make sure you have signed and submitted the Compost Rebate Agreement before submitting any claims.

Please provide the name to whom we will address the check.
Please provide the address to which we will mail the check.
In case of questions, this will be the primary method we will use to contact you.
In case of questions, providing a number may help to process your rebate more quickly.
Please provide your most recent W9 when submitting your first claim. Once we have it on file, you do not need to submit another W9 for all following claims in the calendar year. As a public agency, we require a W9 to transfer you public funds.
A receipt or invoice from the compost facility that includes name of the facility, date of purchase, and quantity (cubic yards) of compost purchased.

Questions? Suggestions for improvement?

Please contact Xinci Tan at or 707.565.1733.