All ADU Regulations

San Rafael, California

San Rafael has updated its ADU ordinance to comply with new state laws. Below are the up-to-date requirements to build an ADU in the city.

September 25, 2023
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San Rafael, CA

The ADU market in San Rafael, CA is growing rapidly due to the city's commitment to increasing housing supply, the high cost of housing in the area, and the attractive option for homeowners to generate extra income or house aging parents. San Rafael’s ADU market is expected to continue to grow in the coming years, and the city is planning to make it even easier for homeowners to build ADUs. Take a look at the ADU requirements in San Rafael, as of 2023.

General ADU requirements

All standard ADU types – detached, attached, and conversion – as well as JADUs are permitted in San Rafael. The specific requirements for your project will depend on the ADU type. ADUs must be equipped for independent living and have permanent facilities for:

  • Living
  • Eating
  • Sleeping
  • Sanitation (i.e. a bathroom)
  • Cooking
  • Exterior access that is separate from the primary dwelling

ADU kitchens must also have:

  • A sink with running water
  • Countertops and cabinetry of a reasonable size
  • A refrigerator
  • A permanent range/cooktop that doesn’t need more than 120V or natural/propane gas
  • JADUs may share bathroom/sanitation facilities with the primary dwelling, but they must have a separate entrance. Conversion ADUs must also have their own entrance.


All properties zoned for single family or multifamily may be eligible to build ADUs.


During the course of permitting your ADU project, you can expect to pay the following fees:

  • Impact fees are waived for ADUs less than 750 sq. ft.
  • School fees are waived for ADUs less than 500 sq. ft.
  • There is a fixed $300 fee planning review for both ADUs and JADUs
  • Building fees are based on ADU valuation and can range between $2,000 - $5,000.

Number of units

The number of ADUs you’re able to build depends on how your lot is zoned:

  • Lots zoned for single family use may add 1 ADU and 1 Jr. ADU (JADU).
  • Lots zoned for two-family or multi-family may add up to 2 detached ADUs per lot or up to 25% of the existing units in the building if conversions of existing non-living space.

Building size

The maximum ADU you can build depends on the ADU type:

  • The maximum size is 500 sq. ft. for a JADU
  • 1,000 sq. ft. for a detached ADU
  • Attached ADUs may not exceed 50% of the primary dwelling floor area.

Building height

Detached and Attached ADUs can reach a maximum height of 16 feet.


Conversion of existing unfinished basement space can be used for an attached ADU.


Minimum setbacks of 4 feet from the side and rear lot lines, as well as 5 feet from any existing structures are required for detached ADUs. However, ADUs can have a 3 foot setback if the total structure height is less than 15 feet.


San Rafael follows CA state law, where no additional parking is needed for an ADU if any of the following are true:

  • The ADU is located within one-half mile walking distance of public transit.
  • The ADU is located within an architecturally and historically significant historic district.
  • The ADU is part of the proposed or existing primary residence or an accessory structure.
  • When on-street parking permits are required but not offered to the occupant of the ADU.
  • When there is a car share vehicle located within one block of the ADU.

Fire safety

An ADU can be required to have fire sprinklers installed if any portion of the structure is located more than 150 ft. from the street or if the main dwelling has an existing fire sprinkler system.


Owner occupancy is not a requirement for permitting an ADU from January 1, 2020 until January 1, 2025. This is a great opportunity for rental property owners to increase their rental yield in a cost-effective way.


While long-term rentals are permitted for ADUs, short-term rentals (e.g. Airbnb for less than 30 days) are not permitted in San Rafael.


Do you have a utility easement over your property? Do you have special setbacks? Reach out to us and we’ll help you build a custom ADU to fit your unique property characteristics and local regulations!


How close to my house can I build an ADU in San Rafael?

When building a detached ADU, it should be at least 5 ft. away from existing structures. You cannot build a detached ADU in within the front setback area of a multi-family home. It is a good idea to check such requirements with local authorities before starting your project.

Can I convert my garage into an ADU?

Yes, if you own a single-family home in a residential-zoned area, you may convert your garage into an ADU. Depending on the condition that your garage is in, the project may take under 9 months to complete and cost less than building a detached ADU. Reach out to our team to get an assessment on the condition of your garage and whether it can be converted affordably.

What is the smallest ADU I can build in San Rafael?

Across California, the smallest ADU you may build is 150 sq. ft., regardless of type.

Does an ADU need a kitchen in San Rafael?

Yes, ADUs must accommodate permanent and independent living, and be equipped with a fully functional kitchen.

Can I build 2 ADUs on my property in San Rafael?

If your property is zoned for single-family living, then you may be eligible to build one ADU and one Jr. ADU (JADU). Multi-family properties may be able to build more detached and conversion ADUs, based on the number of dwelling units already on the property. Reach out to our team for an assessment on how many.

What is the difference between an ADU and a JADU?

ADUs may either be attached to or detached from the primary dwelling, while JADUs are contained entirely within the primary dwelling. ADUs must be equipped with permanent facilities for independent living, but JADUs need only have an “efficiency” kitchen and may share some facilities with the primary dwelling. The maximum size allowed for a JADU is 500 sq. ft., while two-bedroom ADUs in San Rafael may be up to 1,000 sq. ft.

How much does an ADU increase property taxes in San Rafael?

Thankfully, your existing property will not be reassessed if you build an ADU in San Rafael! You can expect the value of your property to increase after you build your ADU. Since property taxes are often based on property values, this can increase your property taxes. However, any increases will only be based on the value of the ADU itself. Building an ADU will not trigger a reassessment of the value of your main home.

How many bedrooms can an ADU have in San Rafael?

There’s no explicit limit to the number of bedrooms for an ADU in San Rafael, however at the maximum allowable size of 1,000 sq. ft., you’d generally be able to fit 2 nicely sized bedrooms or 3 smaller ones if you get creative.

How long does it take to build an ADU in San Rafael?

The entire process, from start to finish, would depend on the type of ADU you’re building, the scope of your project, and the area you’re building in. In our experience in San Rafael, the permitting timeline ranges from 3-6 months.

Can I rent my ADU in San Rafael?

Yes, many homeowners we’ve worked with in San Rafael rent out their ADUs, given the high demand for housing and high rents. Short-term rentals of less than 30 days are not allowed in San Rafael, but you can rent out your ADU on platforms like Airbnb for 30+ days.

How many square feet can an ADU be in San Rafael?

Depending on the zoning of your property, setbacks and the number of bedrooms you are hoping to include, you may be allowed to build an ADU that has a maximum area of 1,000 sq. ft. in San Rafael.

Can you build a 2 story ADU in San Rafael?

ADUs are limited to 16 ft. in height which does not allow for a 2 story ADU.

Do I need solar on my ADU in San Rafael?

Solar requirements for ADUs were updated for 2023. As of 2023, ADUs below 1,000 sq. ft. (which is currently all ADUs in San Rafael) are likely exempt from solar requirements. All conversion ADUs are exempt from solar requirements.

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