San Marcos, CA Accessory Structures: ADU Rental Restrictions (2026)
Key Facts
- Minimum rental term
- 30 days
- Short-term rentals
- Prohibited on ADUs
- Separate sale
- Barred except under Gov. Code § 66341
- Applies to
- Standard ADUs; Junior ADUs governed by O.4
- Governing section
- Municipal Code § 20.410.060.H
Summary
San Marcos bans short-term rentals of accessory dwelling units outright. Municipal Code § 20.410.060.H allows an ADU to be rented only for terms of 30 days or longer, and bars selling it separately from the primary home except in narrow state-law circumstances.
H. Rental or Sale of ADU. The ADU may be rented for terms 30 days or longer. The ADU may not be sold separately from the primary dwelling unit except when pursuant to Government Code Section 66341. An ADU may be approved and built at the same time as the primary dwelling unit is approved and constructed. This section shall not apply to Junior ADUs.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).
Full Breakdown
H sets the rental and sale rules for standard ADUs, distinct from Junior ADUs, which are covered separately under subsection O. It states that 'the ADU may be rented for terms 30 days or longer,' which functions as an outright ban on renting a San Marcos ADU as a nightly or weekly short-term rental through platforms like Airbnb or Vrbo. The same subsection bars selling the ADU separately from the primary dwelling unit, except when a sale is authorized under California Government Code Section 66341, the state provision allowing limited ADU condominiumization for qualifying nonprofit or public housing projects.
Subsection H also confirms an ADU can be approved and built at the same time the primary dwelling is approved and constructed, so a buyer isn't required to build the main house first. 4, as part of the recorded deed restriction package, so both ADU types in San Marcos are locked out of the short-term rental market by their governing sections. 410 authorizes.
Violations & Fines
Renting an ADU for less than 30 days, or attempting to sell it separately from the primary dwelling outside the narrow Government Code Section 66341 exception, violates Section 20.410.060.H. Short-term rental use of an ADU is subject to code enforcement action, and a title company or lender is expected to flag an attempted sale of the ADU that isn't paired with the underlying home.
Frequently Asked Questions
Can I list my San Marcos ADU on Airbnb?
Can I sell my ADU as a separate property from my house?
Does the 30-day rental minimum apply to Junior ADUs too?
Sources & Official References
Other rules in San Marcos
California rules heatmap·Compare San Marcos to another location·View the California accessory structures overview
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