Permitting
Phase Five
- 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.
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.
- School District Fees are calculated based on the district and the size of the ADU.
Submit your application
Permitting step 2
Submitting an application is different depending on where you live. Some local Planning and Building Departments have online portals, and others ask that multiple sets of paper copies be submitted in-person. Some fees may be due when submitting your application, and some may be due later. Contact local staff for more details.
After your application is submitted, the first step will be for your local Planning or Building Division to review it for completeness. They will confirm your application is complete (meaning you correctly submitted all required materials and details) and then other departments and agencies will begin their review.
ADUs within the Coastal Zone (which covers parts of unincorporated Marin County) may require a coastal development permit and a hearing with the California Coastal Commission. Use the Marin County Coastal Zone Boundary map to check if you’re in the coastal zone and talk to local staff to see if this applies to your project.
Revise your application
Permitting step 3
Local staff will complete their review and provide any comments. If they require any modifications to your plan, your team will revise and resubmit the application.
Local staff will complete their review and provide any comments within 60 days, although the process is often quicker. Most likely, this review will happen at a staff level (no hearings), but in less common instances, an additional permit or public hearing may be required.
If modifications to your plan are required, your team will revise and resubmit the application. Under state law, agencies/departments reviewing your plans must provide a full set of comments with a list of incorrect items and how those can be fixed. Many local departments allow you to check your permit status online.
Receive your permits
Permitting step 4
After your application is approved, staff will let you know that your permit is ready and how you can receive it. Once you have paid any remaining fees and you have your permit, you can begin construction. Often permits must be displayed at the site. They are usually valid for 180 days and often renew automatically as long as construction is ongoing and inspections are occurring.
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.
FAQs
Find answers to the most frequently asked questions about permitting.
What permits are required for ADUs and JADUs?
Application requirements vary by where you live, but applications 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 an ADU permit application or submittal requirements checklist that outlines all the required documentation and materials that must be submitted. 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 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:
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.
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.
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.
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?
Because the SB-9 law is new, cities are still in progress on determining exactly how they will apply it. To that end, 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?
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. A new state law as of January 2020 indicated 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.
