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(925) 239-4165 ext: 560
Schedule ADU Consultation (925) 239-4165 ext: 560

San Ramon ADUs

Everything about building Accessory Dwelling Units in San Ramon, CA

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San Ramon ADU Guidelines Last Updated 10/13/20

The city government of San Ramon will approve ADUs under California's statewide mandated regulations.
The California Building Code (CBC) 2019 is adopted.


City Hint: The city permitted a total of 4 ADU projects in the past year of 2019, which is below the average compared to other cities in California.

Number of ADUs allowed:

According to state law, all single-family homes are allowed at least one ADU. Additionally, single-family properties which are owner-occupied may create one ADU and one Junior ADU. Also, multi-family properties may now add one ADU per every four existing residential units, so long as they were legally established.

Types of ADUs allowed:

Detached ADU, Attached ADU, Junior ADU are approved. ADUs may be new construction or converted from existing space. JADUs must be converted from existing space.

Lot size:

Residential lots will not be subject to any minimum lot size for Accessory Dwelling Unit (ADU)s by ordinance or of the underlying zoning district. ~ According To AB68

ADU size:

An ADU attached or constructed within an existing building shall be at least 150 sq. feet, but not more than 50% of the net floor area, or 850 square feet, whichever is greater.

A detached ADU studio or one -bedroom unit shall be at least 150 sq. ft. and shall not exceed a maximum of 850 square feet. A detached ADU with more than one bedroom shall contain at least 150 square feet and shall not exceed a maximum of 1,000 square feet.


1. An attached ADU shall conform to the setbacks required of the primary unit within the zone. No additional setbacks are required for the conversion of an existing structure into an ADU.
2. A detached accessory dwelling unit shall be set back a minimum of 20 ft. from the front property line, 4 ft. from the side property line, and 4 ft. from the rear property line


An ADU must have one covered or uncovered parking space in addition to the parking required for the primary unit. The parking space may be located within a required setback on a compliant parking surface or as a tandem space on an existing driveway.
A unit shall not be required to provide parking if:
a. The accessory dwelling unit is located within one-half mile of public transit. (For the purpose of this paragraph, public transit means any established bus stop associated with the bus services available for general public, such as but not limited to County Connection).
b. The accessory dwelling unit is located within an architecturally and historically significant historic district.
c. The accessory dwelling unit is part of the existing primary residence or an existing accessory structure.
d. When on-street parking permits are required, but not offered to the occupant of the accessory dwelling unit.
e. When there is a car share vehicle located within one block of the accessory dwelling unit. (For the purpose of this paragraph, car share vehicle means a passenger vehicle available at a designated location for general public by reservation and with a fee, such as but not limited to vehicles managed by Zipcar.)

Fire Safety:

Per state minimum requirements.

Shape, materials and style:

1. The exterior shall be built in harmony with the immediate neighborhood.
2. Outside access shall not be in the front of the existing building.
3. The ADU shall be designed to minimize potential privacy issues with the neighboring properties, and additional landscape screening may be required.


1. The height of an attached accessory dwelling is based on maximum height allowed in the applicable residential zone.
2. The height of a detached accessory dwelling shall be limited to 16 feet

Design review:

Ministerial review per state standards.

Number of Bedrooms:

Not specified by State Standards.


Rental of the primary or accessory dwelling unit shall not be for a term of 30 days or less unless approved for “lodging uses” pursuant to the zoning ordinance.

Utility connections:

Local health officer approval where a private sewage disposal system is being used, if required. (State requirements)


1. Attached dwelling unit. A dwelling unit that has one or more party
walls in common with another dwelling unit.
2. Detached dwelling unit. A dwelling unit that does not share any walls
in common with another dwelling unit.
3. Secondary unit. An attached or detached rental dwelling unit located
on a lot which contains a single-family dwelling. A secondary unit
shall include provisions for living, eating, sleeping, cooking and
sanitation. A secondary unit is not considered an accessory building as
defined in Division D2 and Division D8 (Glossary).

Allowed Zones:

*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***

Secondary units are permitted in the RC, HR, RE, RS, RM, RMH, and in PD zones for residential uses on lots with a single-family dwelling.

Existing Structures

Non-conforming units. Where the existing dwelling unit constitutes a legal
non-conforming unit, a secondary unit may be constructed only if the nonconformity
is not expanded and the secondary unit meets all current applicable
zoning standards.

Residential Building Code:

The California Building Code (CBC) 2019 is adopted.

San Ramon City Planning Offices

Call/Text ADU Operator (925) 239-4165
Dial Ext: 560
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ADU Design Library

Browse hundreds of models to find the right fit for your property.

ADU Model 468 sqft

W 26 ft L 18 ft

ADU Model 196 sqft

W 14 ft L 14 ft

ADU Model 600 sqft

W 30 ft L 20 ft

Customer Reviews

"Housable has been a great resource regarding my ADU project. I purchased both the Property and Design Reports. In both cases, they delivered as promised and on time."

Ed in Corona, CA

"My experience with Housable was exceptional. The team was extremely helpful and responsive. I am very satisfied and happy to have used these services. As a home owner I do not know the construction lingo or process but the Housable team very kind and helpful and patient with me. My expectations were exceeded. Thank you for everything."

Monica H. in Oakland, CA

"The property report was great! Made me feel like my project is feasible."

Alexandria in Santa Ana, CA

Complete 5-Step Process

Browse hundreds of permit-ready ADU designs and order one to customize to your needs.
Connect with local contractors to get site visits and cost estimates for your project.
Mark up changes to your plans and provide critical info needed to permit your project.
Finalize your project blueprints to submit for building permits.
Select your contractor and build your project.

What our customers say:

Customer Reviews

"My permits were APPROVED, thank you for all your hard work. I am in the process of meeting with contractors. "

Mary S. in San Jose, CA

"I just wanted to let you know that the permit process has been completed and we are currently in the construction phase. The work you guys did was great and I will definitely be using this service again in the future. I will keep you guys updated on anything important. Thanks!"

Patrick L. in Orange County, CA

Detached ADU - Completed in 2020
1,003 sq. ft., 3 bed, 2 bath

Estimate Your ADU Potential
Costs / ROI



* upon completion of ADU


* based on local average price per sqft


* estimated by location


* 30 years / 5% interest rate / 20% down payment


Size: 500 sqft


Appreciation Estimate = (Base Value: $) / (Home's Living Space: sqft) * (ADU's Living Space: sqft)

Rental Estimate = (Rent Per Sqft: $4.49) * (ADU's Living Space: sqft)

Check your property's zoning, browse designs & get contractor estimates for your ADU project:

Everything you need to get accurate estimates from contractors for your ADU project. Get help with ADU feasibility, design, permitting and sourcing contractors for your project in one place.

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