Frequently Asked Questions

Development Standards

What are the differences between an ADU and a Junior ADU?

 Both ADUs and Junior ADUs (JADUs) must be on a permanent foundation and have a separate entrance, a kitchen facility, and living area that is separate from the primary dwelling unit. However, a JADU only requires a smaller “efficiency kitchen”. An ADU must have its own bathroom, while a JADU may have its own bathroom or share the bathroom in the primary dwelling unit. ADUs are allowed on lots with multifamily or single-family dwellings, while JADUs are only allowed on lots with single-family dwellings. ADUs may be conversions of existing space, attached or detached, while JADUs are only allowed as conversions of existing space. The maximum size of a JADU is 500 square feet, while the maximum size of an ADU is 850 square feet for studios and 1-bedroom units and 1,000 square feet for multi-bedroom units.  

How do I find my zoning information?

The City maintains a Zoning Map, which designates zoning districts throughout the City. In addition, zoning district information explaining your setback and site coverage requirements are in the “Development Standards” section of the City’s Zoning Code. These requirements can be found in Section 17.10.020, Development Standards Table. See Zoning and Allowed ADU Types. 

What zones allow ADUs and Junior ADUs?

ADUs can be built by-right in any zone that allows residential uses. ADUs are not subject to lot size requirements, density limitations, or growth-control measures. JADUs can be built within an existing or proposed single-family dwelling by-right in any zone that allows single-family residential uses. This is subject to different rules and requirements depending on the zone.  

What are the requirements for height, setbacks, maximum unit size, and parking?

See the ADU Development Standards flyer for a summary of requirements for each type of ADU.   

What is the maximum allowable lot coverage?

ADUs must adhere to the lot coverage requirements prescribed by the underlying zoning for the lot. Additionally, for ADUs larger than 800 square feet, the ADU together with the primary residence cannot cover more than 50 percent of the lot area.  However, ADUs of 800 square feet or less are not subject to maximum lot coverage requirements. Internal conversions are exempt from lot coverage requirements. 

What are the owner occupancy requirements?

For JADUs, the owner must record a deed restriction that requires the owner to occupy either the primary dwelling or the JADU. There are no owner occupancy requirements for other ADUs. 

Can I convert my garage?

An existing garage can be converted into an ADU or JADU by making the garage space livable in accordance with applicable California Residential Code standards. At minimum, a garage conversion ADU or JADU must include cooking facilities, heating, sanitation (JADU’s may use primary dwelling), hot and cold water, separate entrances, fireproofing (ADU), egress window, vapor barrier, and fire sprinklers where applicable. Consult the City Building Division to determine the requirements for building an ADU or JADU in a garage.  
Utilities

Do I need to upgrade my utility infrastructure when I share a water line?

If your house shares a water line with a neighbor, your property will need to be disconnected from the shared service and a new water service will need to be installed from the City main to the property to serve the primary residence, and the ADU. You may need to upsize your existing lateral water line to serve both your primary dwelling and the new ADU. The water lateral will need to be constructed per City standards and a new water meter for the ADU installed. See water lateral schematic here. 

Do Electrical Panels and Sub-Panels Need to be Accessible?

Electrical panels and sub-panels, also known as circuit breaker panels/sub-panels or service panels/sub-panels, must be accessible to the ADU and JADU. Problems can arise if the ADU or JADU occupant cannot access the electrical panel or sub-panel when a circuit is overloaded, or a fault occurs. Electrical sub-panels serve as a waypoint between the main electric panel and branch circuits further down the electrical line and can be installed in a secondary location on your property to be accessible to the ADU or JADU. 
Process

How do I get help designing an ADU or Junior ADU?

Begin by looking for a design professional who can help design your ADU. A design professional could be an architect, designer, design/build firm, or modular/prefabrication company. Once you have met with the design professional and shown them your design ideas and lot limitations, they can help draw up preliminary designs for your ADU or JADU. The ADU Center is a local nonprofit that provides support to homeowners interested in building an ADU or JADU. Click here to learn more about the resources they provide. 

What is the timeline for ADU or Junior ADU development?

Most projects take one to two years to complete, but there are different aspects of the project that can change that timeline. Typically, it takes owners up to three months to hire the key players on their team, and the following one to six months developing plans and a submitting complete ADU or JADU application. The number of rounds of review and your team’s timely response to City comments will dictate how quickly the team can start construction. Traditional construction of an ADU or JADU will take between six months and one year. 

What fees does the City collect for ADU and Junior ADU development?

A detailed fee estimate will be provided to you after you submit a complete application. For budget purposes, however, you can expect to pay 3-5% of your overall construction costs toward fees. While the City does charge building, planning and engineering fees, the City does not collect development impact fees for ADUs and JADUs.   

Can I get more time to fix an issue with my ADU identified by Code Compliance?

You can request a delay in code compliance, subject to certain findings. See Section 17.07.020.X.12 of the City’s Municipal Code for further details. 

Can I legalize an unpermitted ADU or Junior ADU?

Yes, legalizing existing, unpermitted ADUs or JADUs is encouraged! Contact the Planning Division for more information about requirements for getting an unpermitted ADU legalized. 

What if I have more questions?

The Building team are available to answer your questions. 

Building Division

City of Rohnert Park Development Services – Building Division
130 Avram Ave.
Rohnert Park, CA 94928
Phone: (707) 588-2240
Email: [email protected]