Phase Five
Permitting
- Understand what's required in your permit application
- Know what to expect from application review
- Get started on your application
- Understand the types of fees you may need to pay
Project timeline
The Permitting phase typically takes 1-6 months. Most ADU projects take 12-18 months to complete, but some extend to 24 months or more.
Key Resources for Permitting
Step-by-Step
Prepare your application package
Permitting step 1
Once the initial design and engineering is complete, it is time to apply for a permit. You can learn more about the Permitting process in our ADU Workbook or via our webinar How to Create an ADU Permit Application. Each jurisdiction has its own set of requirements, but in general you’ll need:
- A site plan showing the property boundaries, along with existing structures and the proposed ADU.
- Floor plan of the ADU.
- Elevations, or side-on views of the proposed ADU.
- Drawings showing the construction details of the proposed ADU.
- Any engineering calculations and diagrams. These could include a soils report, civil engineering reports, structural plans, truss calculations or additional reports required by your jurisdiction.
- Energy analysis (Title 24) and CalGreen checklist
- A completed application and a payment for any relevant fees. If the ADU is under 750 square feet, impact fees will be waived, except school fees unless the ADU is less than 500 square feet.
- Most fees, such as plan review and building inspection fees are paid at the time of service, such as when you submit the permit.
- Napa Valley Unified School District fees are approximately $4.00 per square foot and must be paid before application for a building permit.
- NapaSan typically charges approximately $1,000 per 100 sf of new living space as a usage fee.
- School & utility fees in Sonoma County vary widely due to the large number of different districts. Your local Planning staff can help you determine which districts you are in, and how to find out what fees may be charged.
Key Resources
Submit your application
Permitting step 2
Each jurisdiction handles application submission differently, so double-check all details with your local staff. Some places require applications to be submitted online while others require paper copies of various sizes of paper. In most cases you’ll submit all materials at once, but a few jurisdictions require planning or zoning approval before submitting building permit materials.
If you haven’t settled on a General Contractor when the plans are submitted, it is time to begin looking while the jurisdiction is reviewing your plans.
Revise your application
Permitting step 3
Once the application has been submitted, and the fees paid your project will be reviewed by various government departments for comment. Typically, this includes but is not limited to Planning, Building, Engineering, and the Fire Department. They may have comments on the details of your plans and request changes to match current regulations.
The jurisdiction will either approve or deny your building permit within 60 days of submitting for a permit if your submittal package is complete.
Your Build Team (Designer, Engineers, etc.) will respond to those comments either with further explanation or changes to the design and then your plans can be resubmitted.
In most cases, state law no longer allows cities and counties to comment on pre-existing zoning issues unrelated to the ADU. For example, you should not receive comments about correcting the main house or a fence unrelated to the ADU, unless there is an obvious public safety issue.
State law also says that most ADUs must be approved as a “ministerial action.” This means there are no hearings, and no public feedback.
Receive your permits
Permitting step 4
Once your application is approved by all involved parties, all applicable fees are paid (see below) and your Building Permit is issued, you can move onto construction!
Permit & Application Fees
A variety of fees are required for ADUs, such as application fees, impact fees, and others, and the total amount depends on your property. Individual fees typically range from a few hundred dollars to over $30,000. Some fees are based on the details of the project while others are fixed. Surprisingly, your local jurisdiction does not control many of the most expensive fees, like school and water fees, which are assessed by other agencies and dependent on the size or location of your ADU.
You can use our ADU Calculator to help you estimate the fees for your project.
Here are some of the more commonly required fees:
Entitlement fees are levied by cities to cover the administrative costs of applications. These typically range from hundreds to thousands of dollars and are not levied in all cities.
Building permit fees cover the costs of inspections before, during, and after construction. These fees can vary and are often a few thousand dollars. Check with your city for the latest information on fees.
Development impact fees help pay for new infrastructure in your neighborhood and the surrounding area, such as new roads or parks. ADUs under 750 square feet are exempt from these fees.
Water and sewer fees support the cost of providing water and sewer service to the community. Recent changes to state law have significantly reduced the water fees for ADUs: existing buildings do not require water fees, while new buildings can only be charged fees in proportion to the size of the unit.
Related Blog posts
FAQs
Find answers to the most frequently asked questions about permitting.
Are there pre-approved plans I can use?
Yes! We help run ADU Plans Galleries for many of our participating communities. These galleries feature a browsable, filterable gallery of 50 ADU plans, many of which have been pre-approved by your City or County. Your City or County may also have a listing of pre-approved plans on their website. Search for your local gallery or browse the overall statewide gallery at the California Plans Gallery search page.
What permits are required for ADUs and JADUs?
Application requirements vary by where you live, but applications for a new ADU typically include:
- Site plan (depicting existing and proposed structures)
- Building/architectural plans (floor plans, elevation plans, and details)
- Structural plans (foundation plan, framing plans, and associated details)
- Other items (Title 24 energy calculations, deed restriction, address assignment form, or other materials required by your location)
- Deed Restriction filed with the County
- Supplementary Materials
Some local Planning Departments have a specific ADU permit application or submittal requirements checklist that outlines all the required documentation and materials that must be submitted. Conversions of existing living space often require less documentation. Contact local staff to learn about your specific application process and requirements.
How much does it cost to get permits for an ADU?
ADUs can be charged a variety of fees from your local government, the State, and other agencies. Some fees are based on details of the project while others are fixed. The total amount depends highly on your property and plans, but local staff can most likely provide an estimate once you have a good idea of your project details. See the Budgeting and Finance page, our ADU Calculator, and our ADU Workbook for more details.
Are there water or sewer issues I should consider?
Some cities may require homeowners to upsize service and or meters to meet capacity requirements. Check with local Planning & Building staff to learn more about local requirements for utilities.
Can my ADU be stopped because of other noncompliance issues on my property?
In most cases, state law no longer allows cities and counties to comment on pre-existing zoning issues unrelated to the ADU. For example, you should not receive comments about correcting the main house or a fence unrelated to the ADU, unless there is an obvious public safety issue.
What are the issues I should be aware of if my property uses a septic system?
If you are on a septic system, it is important to ensure with your local agency that you have septic capacity to add an ADU or Junior ADU with your desired number of bedrooms before you move forward on plans for your project. Upgrading a septic system can be costly or challenging, and it is good to assess realistic needs upfront. Learn a ton more about septic systems from our detailed blog post on the topic right here. You can do so by reaching out to your local agency:
- For Sonoma County please contact Permit Sonoma Well & Septic at PermitSonoma-Well-Septic@sonoma-county.org or at (707) 565-2849.
- For Napa County please contact the Napa County Environmental Health Division at Environmental@countyofnapa.org or at (707) 253-4417.
If you don’t currently have septic capacity for your ADU project and do not want to upgrade the system, ask your local planning department about the possibility of a “bedroom swap,” which allows you to make construction changes to an existing bedroom in the primary residence to convert it to non-bedroom space (e.g., an office) and then use the newly freed up septic capacity for your ADU. Again, whether or not this is a possibility for you depends on your local jurisdiction and the specific details of your property.
What is Title 24 and how does it affect my ADU project?
Title 24 regulates minimum energy efficiency for new construction in California. For example, these standards dictate how much insulation is required and the types of light fixtures that can be used. All new ADUs will need to demonstrate compliance with Title 24, which usually requires hiring a consultant and typically costs less than $500. For a detailed blog post on Title 24 read here. In some cases, like newly constructed freestanding ADUs, you might need to add solar panels to meet the rules. For a list of Title 24 consultants, check out our Vendor Registry.
What are the solar requirements for ADUs?
Newly constructed ADUs are subject to the Energy Code requirement to provide solar panels if the unit(s) is a newly constructed, non-manufactured, detached ADU. Per the California Energy Commission (CEC), the panels can be installed on the ADU or on the primary dwelling unit. ADUs that are constructed within existing space, or as an addition to existing homes, including detached additions where an existing detached building is converted from non-residential to residential space, are not subject to the Energy Code requirement to provide solar panels.
Please refer to the CEC on this matter. For more information, see the CEC’s website. You may email your questions to: title24@energy.ca.gov, or contact the Energy Standards Hotline at 800-772-3300. CEC memos can also be found on HCD’s website.
For important information for homeowners thinking of going solar, reference the California Public Utilities Commission (CPUC)’s California Solar Consumer Protection Guide.
How does SB-9 impact my ability to build an ADU?
Use of SB-9 to split a lot and build additional housing in dependent on specific conditions of the property and proposed project. Below is some background information on SB-9 to review, and from here we advise you to speak directly with the city to get more information specific to your property and how the city is applying SB-9 as of now. Some information can be found at this Maxable blog post. You can also look at the California Department of Housing and Community Development SB-9 Fact Sheet. Finally, the Casita Coalition webinar on SB-9 is available to watch.
I have an unpermitted ADU on my property, what should I do?
A: Each local jurisdiction has a different Code Enforcement process and protocol with regard to unpermitted ADUs. Many jurisdictions are focused on a collaborative approach to help homeowners bring their ADU up to code. State law requires that local jurisdictions should provide homeowners up to 5 years to bring a unit up to code if the local jurisdiction does not determine that there is a health or safety issue with the unpermitted unit. As of now, in our experience most jurisdictions determine that there is a health or safety issue, so we have not yet seen this delay in enforcement applied. For more detailed information, we recommend watching this on-demand webinar from the Casita Coalition on unpermitted ADUs.
