San Mateo County, CA Landscaping Rules: Composting (2026)
Key Facts
- Applies to
- Single-family homes, densely populated areas
- Alternative
- On-site composting instead of collection
- State authority
- CCR Title 14, Div 7, Ch 12
- Oversight
- County may inspect, adjust service
Summary
Single-family organic waste generators in the county's densely populated unincorporated areas may compost yard and food waste on site instead of subscribing to hauler collection, per county code.
Organic waste Generators may additionally manage their Organic Waste by preventing or reducing their Organic Waste, managing Organic Waste on site, and/or using a Community composting site pursuant to CCR Title 14: Natural Resources, Division 7, Chapter 12, Section 18984.9(c).
(d) Shall participate in the County's Organic Waste Collection Service(s) by placing designated materials in designated containers as described below and shall not place Prohibited Container Contaminants in collection containers.
1. Option 1: A three- and three-plus-container collection service as described in either option 1(i) and 1(ii) below:
i. Generator shall place Source Separated Organic Waste, including Food Waste, in the Green Container; Source Separated Recyclable Materials in the Blue Container; and remaining materials (excluding Excluded Waste) in the Gray/Black Container. Generators shall not place materials designated for the Gray/Black Container into the Green Container or Blue Container.
ii. Generator shall place Source Separated Organic Waste, except Food Waste, in the Green Container; Source Separated Recyclable Materials in the Blue Container; and Mixed Waste, including Food Waste, in the Gray/Black Container. Generator shall not place materials designated for the Green Containers or Blue Containers in the Gray/Black Containers.
2. Option 2: Two-container collection service (Green Container/Gray Container system
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 47).
Full Breakdown
San Mateo County Ordinance Code § 4.04.140(c) lets single-family Organic Waste Generators in densely populated unincorporated areas manage their organic waste by preventing or reducing it, composting on site, or using a community composting site, instead of full hauler collection, consistent with the state's SB 1383 organics rules under CCR Title 14, Division 7, Chapter 12, Section 18984.9(c).
Violations & Fines
Generators who don't properly separate or manage organic waste can be required to adjust their collection service level after a County inspection, per § 4.04.140(b).
Frequently Asked Questions
Can I compost at home instead of using the green cart?
Does the county check compliance?
Sources & Official References
Other rules in San Mateo County
California rules heatmap·Compare San Mateo County to another location·View the California landscaping rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.