How San Jose Handles Accessory Structures: A Practical Guide

San Jose maintains 273 local ordinances across all categories, and 9 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where San Jose falls on the strict-to-permissive spectrum compared to other cities.

Tiny Homes

San Jose permits tiny homes on foundations as Accessory Dwelling Units under California Government Code §65852.2 and local ADU ordinance. Movable tiny homes on wheels (THOWs) can qualify as ADUs if they meet ANSI 119.5 or HUD standards and are installed with utilities. Homeless tiny-home villages operate under city-sanctioned programs.

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Specific penalty amounts for this ordinance are not published in a publicly accessible fine schedule. Contact [San Jose code enforcement](https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=65852.2&lawCode=GOV) directly for current fines, enforcement procedures, and hearing options.

ADU Rules

San Jose regulates ADUs and JADUs under San Jose Municipal Code §20.30.150, originally updated by the City Council in mid-2018 and amended to track state law. Detached ADUs are capped at 1,200 sq ft (on lots of 9,000 sq ft or larger; 1,000 sq ft cap on smaller lots), and JADUs at 500 sq ft within the primary single-family dwelling.

Key details: Code Section: SJMC 20.30.150. Max Detached (lot 9,000+): 1,200 sq ft. Max Detached (smaller lot): 1,000 sq ft. Max JADU: 500 sq ft. Height (1-story / 2-story): 18 ft / 24 ft.

Unpermitted ADUs are code violations enforced by San Jose Code Enforcement with stop-work orders, administrative citations, and required compliance. Renting an ADU for fewer than 30 days violates state ADU law and San Jose's short-term rental rules.

San Jose is more permissive than most cities when it comes to adu rules. That said, there are still limits.

Garage Conversions

San Jose allows conversion of an existing garage to an ADU or JADU under SJMC §20.30.150, consistent with California Government Code §65852.2. No replacement parking is required when an existing garage is converted to an ADU, and the existing setbacks are preserved for the conversion footprint.

Key details: Code Section: SJMC 20.30.150; Cal. Gov Code §65852.2. Replacement Parking: Not required. Existing Setbacks: Preserved for conversion. JADU Max Size: 500 sq ft (attached only). Min Rental Term: 30 days.

Converting a garage to habitable space without a building permit is a code violation under San Jose Building Code, subject to stop-work orders, fines, and potential requirement to permit the work or restore the garage. Using a converted-garage ADU for stays under 30 days violates SJMC 20.30.150 and the city's STR rules.

The rules around garage conversions in San Jose lean permissive, but that does not mean anything goes.

Carport Rules

San Jose regulates carports as part of off-street parking under San Jose Municipal Code Chapter 20.90 (Parking and Loading), with the citywide parking minimum repealed by the Council on December 6, 2022 and effective April 10, 2023. Carports built as accessory structures are still permitted but no longer mandated, and the standard 90-degree parking stall under Table 20-220 is 9 feet wide by 18 feet long.

Key details: Parking Code: SJMC Ch. 20.90 (Parking & Loading). Stall Size (90 degrees): 9 ft x 18 ft, Table 20-220. Minimum Parking: Repealed effective April 10, 2023. ADU Replacement: Not required when carport converted to ADU. Permit Required: Building permit via Development Services.

Building a carport without the required building permit, or one that fails to meet the zoning setbacks in SJMC Chapter 20.30, is a violation enforced by the Code Enforcement Division and can result in a Notice of Violation, mandatory permit-after-the-fact fees, and administrative citations escalating from approximately $100 for a first offense to $200 and $500 for second and subsequent violations under SJMC Chapter 1.08, plus orders to remove unpermitted construction.

San Jose is more permissive than most cities when it comes to carport rules. That said, there are still limits.

ADU Permits

San Jose processes ADU applications ministerially under San Jose Municipal Code Section 20.30.150 with a 60-day decision deadline mandated by California Government Code Section 65852.2. Detached new-construction ADUs are capped at 800 sq ft with a 4-foot rear and side setback. Conversions of existing space (garage, basement) face no separate setback, and attached ADUs may reach 1,200 sq ft or 50 percent of the main dwelling, whichever is less. Submittal is through the Permit Center.

Key details: Governing Section: SJMC 20.30.150. Review Type: Ministerial, 60-day clock. Detached Max Size: 800 sq ft. Detached Setback: 4 ft rear and side. Pre-Approved Plans: Available.

Building an ADU without a permit triggers a Stop Work Order from the Building Division and double permit fees on the after-the-fact application. Unpermitted ADUs that cannot be retroactively permitted must be removed or restored. Code Enforcement may issue administrative citations of $100 to $500 per day until compliance.

The rules around adu permits in San Jose lean permissive, but that does not mean anything goes.

ADU Impact Fees

Under California Government Code Section 65852.2(f)(3) and San Jose Municipal Code Section 20.30.150, ADUs under 750 sq ft are exempt from all city impact fees including the Building and Structure Construction Tax, the Commercial-Residential-Mobile Park Tax, and park dedication fees. ADUs of 750 sq ft or larger pay impact fees prorated by floor area relative to the primary dwelling. Utility connection fees are capped for conversions of existing space.

Key details: Under 750 sq ft: All impact fees waived. Authority: Gov. Code 65852.2(f)(3). 750 sq ft and Up: Prorated by floor area. Conversion ADUs: Most utility fees avoided. School Fees: District sets, often >500 sq ft only.

Failing to pay assessed fees before permit issuance simply prevents the permit from being issued. There is no penalty per se. If an unpermitted ADU is later legalized, all otherwise-applicable fees are collected based on the current schedule plus a double-fee penalty for after-the-fact processing.

If you are coming from a city with tighter rules, you will find San Jose gives residents more flexibility on adu impact fees.

ADU Owner Occupancy

Standard ADUs permitted between January 1, 2020 and January 1, 2025 carry no owner-occupancy requirement under California Government Code Section 65852.2(a)(6) and SJMC 20.30.150. AB 976 (2023) made that prohibition on owner-occupancy mandates permanent. Owners may rent both the main house and the ADU to separate long-term tenants. Junior ADUs (JADUs) up to 500 sq ft within the primary dwelling still require the owner to live on-site in either the JADU or the main house.

Key details: Standard ADUs: No owner-occupancy required. Authority: AB 976 (2023), Gov. Code 65852.2(a)(6). Junior ADUs: Owner occupancy required. JADU Size Cap: 500 sq ft, inside main house. Recording: JADU deed restriction.

There are no city-imposed owner-occupancy violations for standard ADUs. For JADUs, owner occupancy is enforced through a recorded deed restriction. Renting both the JADU and the main house simultaneously, or selling the JADU separately from the main dwelling, breaches the deed restriction and exposes the owner to civil enforcement by the city.

San Jose is more permissive than most cities when it comes to adu owner occupancy. That said, there are still limits.

ADU Rental Restrictions

San Jose prohibits short-term rentals of ADUs and JADUs. Under SJMC 20.30.150 and SJMC 20.80.460, both ADUs and Junior ADUs may only be rented for terms of 31 days or longer. Hosted short-term rentals (under 30 days) are only allowed in the primary dwelling. Long-term rentals of standard ADUs face no owner-occupancy requirement, but JADUs remain tied to owner occupancy of either unit.

Key details: ADU STR Status: Prohibited. Minimum Rental Term: 31 days. Governing Sections: SJMC 20.30.150, 20.80.460. First-Offense Penalty: $1,500. JADU Rental Term: 31+ days only.

Operating an ADU as an Airbnb/Vrbo is a code violation under SJMC 20.80.460. First-offense administrative penalty is $1,500; subsequent violations within 12 months escalate to $3,000 per occurrence. The city may also revoke the underlying STR registration on the primary dwelling and refer for misdemeanor prosecution under SJMC 1.08.010.

Compared to other cities, San Jose takes a harder line on adu rental restrictions. The enforcement and penalty structure reflects that.

Shed Rules

Sheds in San Jose count toward rear yard coverage. Total rear yard structure coverage may not exceed 40% or 800 sq ft (whichever is greater). Structures over 650 sq ft need a Special Use Permit.

Key details: Max Coverage: 40% of rear yard or 800 sq ft. Permit Threshold: 650+ sq ft = Special Use. Electrical/Plumbing: Always needs permit. Code: SJMC §20.30.500.

Unpermitted structure: retroactive permit with penalty. Non-compliant setback: modification or removal. Habitation violation: immediate correction.

The Bottom Line

Compared to many U.S. cities, San Jose gives residents more room on accessory structures. 6 of the 9 rules here are rated permissive. But permissive does not mean unregulated. There are still requirements, and the city does enforce them when violations are reported.

Keep in mind that San Jose can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.