How to Prepare Your ADU Plans for San Diego Permit Approval

You need a permit before you start digging.  The process for getting an ADU permit in San Diego is a lot easier now that the new rules went into effect in 2025. But only if your plans meet city or county standards. If you live in the City of San Diego or anywhere else in the county, the process includes checking the zoning, making architectural plans, submitting them digitally, and having the city review them. If you skip a step or send in plans that aren't complete, you'll have to deal with delays, corrections, and headaches.

Most homeowners in San Diego City have to follow city rules, but the county around it (including unincorporated areas) has its own rules about ADU size, setbacks, building separation, and even pre-approved floor plans.  When you compare the two:

If you live near the city or county line, start with the ADU handbook for your area.  Check again for any recent changes. San Diego changed a number of ADU rules in mid-2025, including the bonus program and faster approvals.  The best places to find information are official websites, local design-build blogs, and professional ADU guides.

• Site Plan: The property lines, the distance between the ADU and the main house, and the location of the ADU in relation to the main house. 
• Floor Plan: The layout of the rooms, the size of the rooms, and the location of the windows.
• Elevations: Views of the outside from all sides
• Structural Plans: Details about the framing, foundation, and roof
• Title 24 Energy Calculations: Following California's energy code
• Engineering Reports: If needed, like soils or stormwater plans (which is rare for most San Diego ADUs)

• Filled out application form - ADU checklist from city/county website - Proof of ownership (deed or tax bill) - Digital PDF set of plans
• Sometimes pictures of the site
• Form for notifying neighbors (for some areas)
• A signed energy certificate (Title 24)

Both the county's digital platform and San Diego's Development Services Portal let people upload files online.  You can do it in person, but it will take longer.  The city usually gives feedback or corrections within 60 days of submission for most projects. For coastal or multifamily lots, it may take longer.  Under the new AB1332 rules, plans that use pre-approved templates can be looked at in as little as 30 days.

Most plans need to be changed in some way.  City or county reviewers will tell you if there are problems with egress windows, setbacks, energy compliance, or missing sheets.  If you want to keep your place in line, you need to make corrections quickly.

In 2025, the price will be between $6,500 and $21,000, depending on the size, complexity, and number of extra units.  For units smaller than 750 square feet, there are no impact fees.  For units larger than 500 square feet, there are school fees.  ADUs pay less for water and sewer than regular homes.  Before construction starts, you will pay the last fees.

You can start building as soon as you have the permit.  There will be inspections at important points, like the foundation, framing, and final sign-off.  Stick to your approved plans, or ask for changes if you need to make big ones.

• Missing Documents: Always check the most recent checklist. If you forget to send a neighbor notification form or a Title 24 sheet, it will take longer.
• Zoning Surprises: Some properties may have overlay zones, such as coastal, historic, or environmentally sensitive areas, that make getting a permit harder.
• Plan Conflicts: Do you use online plan generators?  Get a licensed professional to check that they meet the most recent building codes.
• Mistakes in Size and Setback:  Never guess; always check with the mapping tool for your city or county.

• Lowering of Permit Fees: Small units don't have to pay impact fees, and school fees are based on how many students they have.
• Plans that have already been approved: Cities must accept ADU plans that have already been approved by other California areas.  These templates should be reviewed more quickly.
• Rules for owner-occupancy: Most permits are now permanently removed, making it easier to rent or invest in ADUs.
• Affordable Bonus Program: For every deed-restricted affordable ADU, you can get one extra ADU that is not restricted. However, this is only possible in high-density areas.
• Condo Sale Option (AB1033): ADUs that the city has approved can now be sold as condos, which is a big change for people who want to sell.

Yes, the city or county must give you a permit for every new building or garage conversion.  You could get fined and lose money on your property if you don't have a permit.

Yes, the City of San Diego now accepts plans that have been pre-approved by nearby jurisdictions, as AB1332 says it must.  This can cut the time it takes to get approval in half.

• Full set of digital architectural plans
• A site plan that shows the setbacks, dimensions, and locations
• Certificate of compliance with energy standards - Verification of ownership
• Pictures or surveys (sometimes)
• A list of things to do and a permit application

If the main home has solar panels, detached ADUs in San Diego must have them too. If the main home has fire sprinklers, the ADUs must have them too.  The rules for the county are the same as the rules for the city when it comes to fire safety and energy use.

No, city fees range from $6,500 to $21,000 as of 2025. County fees are similar, but they might have lower water and sewer costs.  In all of California, units that are less than 750 square feet do not have to pay impact fees.

• When you can, use pre-approved plan templates to speed up the review process.
• Send all of your documents in digital form to avoid delays in person.
• Correct mistakes quickly and accurately; mistakes start the review clock over.
• Check local overlay zones (coastal, historic) again to see if they have any extra permit requirements.
• Add energy and accessibility improvements to your ADU to make sure it meets code and stays valuable in the future.

To get your ADU plans approved by the city of San Diego, you need to pay attention to changes in the law, make sure you have all the paperwork you need, and use streamlined processes like pre-approved plans strategically.  Following the rules will speed up the permit process and increase the value of your property. This includes knowing the latest city fees and how to submit your application online, choosing the right size and type of property, and getting around coastal zone problems.  Use the best SEO keywords to get the most visibility online, and use the bonus programs and plan templates to get the best chance of getting approved without any problems in 2025.