Architectural & Design Studio

How to Calculate ADU Permit Fees For Your California Municipality

12/25/20233 min read


silver and gold round coins in box
silver and gold round coins in box

A couple of years ago, if you asked whether you could build an ADU on your residential property, you may have gotten an ambiguous answer. It all depended on the local permitting and zoning regulations. Some California cities made it relatively easy to build, but others charge exorbitant permitting fees, sometimes more than the cost of the ADU itself. In some cities, fees could be as high as $50,000.

In addition, they required large minimum lot sizes that made construction very difficult for the average homeowner. However, in recent years, the state of California has recognized the need for more affordable housing options and has implemented legislation to make it easier for homeowners to build ADUs.

Understanding ADU Permit Fees

Before diving into the specifics of calculating ADU permit fees, it's important to understand what these fees are and why they exist. Permit fees are charges imposed by the local municipality for reviewing and approving construction projects. These fees cover the cost of the permit application process, plan reviews, inspections, and other administrative tasks.

ADU permit fees can vary widely between different municipalities in California. Factors such as the size of the ADU, the complexity of the project, and the location can all influence the final cost of the permit.

Calculating ADU Permit Fees

Calculating ADU permit fees for your specific municipality can be a bit complex, as each city may have its own fee structure and calculation methods. However, here are some general steps you can follow to get an estimate of the permit fees:

  1. Research the local municipality's website: Start by visiting the official website of your city or county. Look for the building or planning department section, as they often provide information on permit fees and requirements.

  2. Find the ADU permit fee schedule: Look for a fee schedule specifically for ADUs. This should outline the different types of fees and their corresponding amounts.

  3. Determine the size and type of your ADU: Measure the square footage of your proposed ADU and determine its classification (e.g., attached, detached, or conversion).

  4. Calculate the base permit fee: Most municipalities charge a base fee for ADU permits. This fee is typically based on the size of the ADU and can be calculated by multiplying the square footage by a predetermined rate.

  5. Add additional fees: Depending on your specific project, there may be additional fees for things like plan reviews, inspections, and impact fees. These fees are often based on a percentage of the base permit fee.

  6. Consider other factors: Some municipalities may have additional requirements or fees based on factors like the location of the ADU or whether it will be used for affordable housing.

  7. Consult with a professional: If the permit fee calculation process seems overwhelming or if you want to ensure accuracy, consider consulting with a professional such as a local architect or contractor who has experience with ADU projects in your area.

Additional Considerations

While the steps outlined above can give you a general idea of how to calculate ADU permit fees, it's important to note that there may be additional factors to consider. Here are a few additional considerations:

  • Fee waivers or reductions: Some municipalities offer fee waivers or reductions for certain types of ADUs, such as those designated for affordable housing or for homeowners with low incomes. Check with your local municipality to see if you qualify for any fee reductions.

  • Impact fees: In some areas, there may be impact fees associated with ADU construction. These fees are meant to offset the impact of additional housing units on local infrastructure, such as schools and utilities.

  • Timing: Keep in mind that permit fees may change over time. It's a good idea to check with the local municipality for the most up-to-date fee schedule before beginning your ADU project.

Remember, calculating ADU permit fees is an important step in the process of building an ADU on your residential property. By understanding the fee structure and following the steps outlined above, you can get a better idea of the costs involved and plan your project accordingly.

Building an ADU can be a great way to create additional living space or generate rental income. While permit fees can add to the overall cost, the benefits of having an ADU often outweigh the financial investment. So, don't let permit fees discourage you from exploring this housing option.




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