San Mateo County, CA Cannabis Regulations: Home Cultivation (2026)
Key Facts
- Plant Limit
- 6 per residence
- Location
- Indoor only: no outdoor
- County Code
- Chapter 5.148
- Age
- 21+ (MAUCRSA)
- Sale
- Requires commercial license
Summary
Unincorporated San Mateo County allows adults 21+ to cultivate up to 6 cannabis plants per residence for personal, non-medical use under County Code Chapter 5.148 (Personal Cultivation). Cultivation must occur inside a private residence or a fully enclosed and secure accessory structure. OUTDOOR personal cultivation is PROHIBITED in unincorporated San Mateo County, going further than state law's baseline. Qualified medical patients may also cultivate indoors. Sale or commercial distribution requires a commercial cannabis license, which the County does NOT issue for retail activities.
11362.2. (a) Personal cultivation of cannabis under paragraph (3) of subdivision (a) of Section 11362.1 is subject to the following restrictions: (1) A person shall plant, cultivate, harvest, dry, or process plants in accordance with local ordinances, if any, adopted in accordance with subdivision (b). (2) The living plants and any cannabis produced by the plants in excess of 28.5 grams are kept within the person’s private residence, or upon the grounds of that private residence (e.g., in an outdoor garden area), are in a locked space, and are not visible by normal unaided vision from a public place. (3) Not more than six living plants may be planted, cultivated, harvested, dried, or process
Full Breakdown
California Proposition 64 (2016) and the Medicinal and Adult-Use Cannabis Regulation and Safety Act (MAUCRSA, 2017) allow adults 21+ to cultivate up to 6 plants per residence. 148 restricting personal cannabis cultivation as follows: permitted only indoors inside a private residence or a fully enclosed, secure accessory structure on the residential grounds; outdoor cultivation (visible or not) is expressly PROHIBITED countywide. The indoor area must be locked and secured from unauthorized access including by minors. Odor must be controlled so it does not drift off-site (carbon filters or sealed systems).
Electrical modifications for lighting, ventilation, or climate control require building/electrical permits. Qualified medical patients with a physician's recommendation may cultivate for personal medical use under the same indoor-only restrictions; there is no enhanced plant count. Landlords may prohibit cannabis cultivation in rental units per lease terms. HOAs may also prohibit. Cultivation for sale or distribution without a commercial license is a crime under H&S Code §11358.
Violations & Fines
Outdoor personal cultivation: County Code Chapter 5.148 violation, $100-$500 first offense, escalating for repeat. Exceeding 6 plant limit: citation and plant abatement. Unsecured cultivation accessible to minors: misdemeanor H&S §11357.5. Cultivation for sale without license: felony H&S §11358. Unpermitted electrical work: building code violation plus possible fire code liability.
Frequently Asked Questions
Can I grow cannabis in my backyard if it's fenced?
Do I need a permit to grow indoors?
Sources & Official References
Other rules in San Mateo County
California rules heatmap·Compare San Mateo County to another location·View the California cannabis regulations overview
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