The Hidden Costs of ADU Projects in San Diego—Revealed

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12 min read

Planning an ADU in San Diego? Get the lowdown on all the hidden costs that can catch you off guard, including utility connection fees and unexpected regulatory expenses.


Understanding the ADU Cost San Diego is critical for planning and budgeting. Navigating the ADU cost environment can be difficult, from building prices to permitting fees, financing alternatives, to ongoing costs. Make informed decisions by being informed.

Better Place Design & Build can provide realistic pricing estimates based on your project specifications. Contact San Diego County’s Department of Planning and Development Services for the most up-to-date information on permit fees and restrictions.

Permitting Fees in ADU Cost San Diego Project

Permitting and costs are required when constructing an ADU in San Diego. Permit fees can vary depending on the specific conditions set by the city and other regulatory organizations. ADU Cost San Diego Project fees may include:

  • Plan Check costs

These costs cover evaluating and approving the ADU construction plans. The size and complexity of the project usually determines the amount.

  • Development Impact Fees

You may be required to pay development impact fees for ADUs, which contribute to infrastructure upgrades and public services. These fees can vary depending on the location and size of the ADU.

  • Utility Connection Fees

Paying connection fees to utility providers such as water, electricity, and sewer lines may be required when connecting the ADU to services such as water, electricity, and sewer lines. The specific requirements and the existing infrastructure will determine the expenses.

  • Building Permit Fees

These are the costs of getting the building permit for the ADU development. Typically, the cost is computed based on the project’s valuation, which is decided by criteria such as size, materials, and construction expenses.

  • Other Fees

Other fees, such as fire department fees, school fees, or impact fees particular to specific zones or districts, may apply depending on the project. These fees can vary and should be factored into the ADU project budget.

ADU San Diego Financing and Loan Options

There are several ways to finance ADU Cost San Diego project in San Diego. Consider the following popular funding and loan options:

  • Personal Savings

Using personal savings or financial reserves to support an ADU project is a simple method to get started. It does away with the necessity for loan applications, interest payments, and possible debt.

  • Home Equity Loans or Lines of Credit

If you have equity in your primary residence, you may qualify for a home equity loan or a home equity line of credit (HELOC). With these loans, you can borrow against the value of your house, generally up to 80% of the appraised value minus any outstanding mortgage balance. Home equity loans frequently have fixed interest rates and repayment terms, but HELOCs offer a line of credit that can be relied on as needed.

  • Construction Loans

These loans can help you cover the costs of constructing an ADU. They may have higher interest rates than typical mortgages, and the payback terms may vary. Construction loans frequently have two phases: the construction phase, in which money is disbursed while building advances, and the permanent phase, in which the loan is turned into a mortgage once construction is completed.

  • Refinancing Existing Mortgages

By refinancing, you can raise the amount of your loan while perhaps achieving a cheaper interest rate or modifying the repayment terms. This option is advantageous if you have adequate home equity and can obtain more favorable terms than your current mortgage.

  • Government Programs and Grants

These programs attempt to promote affordable housing and encourage the construction of ADUs. It’s worth investigating local housing projects and contacting the San Diego Housing Commission to inquire about any relevant financial help programs.

When weighing financing choices, consider the interest rates, payback terms, fees, and associated eligibility conditions. Consulting with financial institutions, mortgage brokers, or housing counselors can help you choose the best financing choice for your ADU Cost San Diego project.

Make informed decisions with your ADU project costs

Better Place Design & Build will assist you in making an informed decision by acquiring all of the vital information on the ADU Cost San Diego project. Begin designing your ADU project soon to get the benefits of additional housing and potential rental income. Inquire now!


Construction materials, labor, design and architectural services, permits and fees, utility connections, impact fees, and finance charges are all key cost components. Each of these elements contributes to the overall project cost.

Prefabricated or modular ADUs may be more cost-effective. These units are built off-site and brought to the property, reducing building time and potential expenses. However, the total cost will be determined by criteria such as the pre-fabricated ADU’s size, style, and customization options.

Yes, in some cases, you may be able to convert an existing structure, such as a garage or a portion of your home, into an ADU.  However, it’s essential to ensure that the existing structure meets the necessary requirements and can be converted into a habitable space while complying with building codes and regulations.

Yes, renting out the ADU can help cover construction costs over time. Due to the increasing demand for housing in San Diego, ADUs are a popular rental choice. Rental income from the ADU can help with housing affordability and provide a source of revenue for homeowners.


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