The cost and return on investment (ROI) of building an Accessory Dwelling Unit (ADU) in Los Angeles can vary based on several factors, including the size of the ADU, construction materials, labor costs, permits, and location. Here is some general information to give you an idea, but keep in mind that specific costs can vary significantly.

1. Construction Costs:

The cost of building an ADU depends on design, complexity, finishes, and the quality of materials, and construction costs in Los Angeles tend to run higher than elsewhere. There is no credible single number that applies to every home, and a contractor who gives you a firm total over the phone is guessing.

2. Permitting and Design Costs:

Modern ADU interior with open kitchen and living space

There are several permits and fees required when building an ADU in Los Angeles, and the total depends on your project's size, scope, and location — confirm the current fee categories and amounts with LADBS before you budget. Additionally, you may need to hire an architect or designer to create the ADU plans, which is a separate design cost on top of the permit fees.

3. Utilities and Infrastructure:

You may need to make additional investments in utilities and infrastructure for the ADU, such as connecting to water, sewer, and electrical systems. These costs can vary based on the distance from the main lines and the existing capacity, and there is no credible single figure without a review of your specific connections.

4. Financing Costs:

If you require financing to build your ADU, you should consider the associated costs, such as loan interest rates, origination fees, and any other charges from lenders or financial institutions.

ROI considerations:

The ROI of an ADU in Los Angeles can be substantial due to the high demand for housing and rental properties. The potential return on investment can come from rental income, increased property value, and potential tax benefits. ADUs in desirable locations and with desirable amenities may command higher rents and generate a more significant ROI.

However, it's crucial to note that the ROI can be influenced by factors like construction costs, ongoing maintenance, vacancy rates, rental market conditions, and property management costs. It's advisable to conduct thorough research and consult with professionals to evaluate the potential ROI specific to your property and circumstances.

Overall, ADUs in Los Angeles have the potential to provide a favorable return on investment, but it's essential to consider all the associated costs and local market conditions to make an informed decision.