There are several things to consider before building an ADU in Los Angeles. ADU permits and eligibility will need to be approved before you can start your project.

A building permit gives you permission to construct your ADU, proving that it complies with local zoning, building, and residential codes.

The cost of a permit is directly related to the cost of the construction of your ADU project.

Discussed below is the ADU permit process and an estimate of your Los Angeles ADU permit cost.

How Much Does an ADU Permit Cost in Los Angeles?

On average, the cost in Los Angeles for an ADU permit is around $8000 for a 1,200-square-foot unit. Permit costs can be anywhere between $1000 to up to $20,000 depending on the size of your unique property, design costs, and the area in which you are building.

ADU permit costs are determined by :

  • Type Of Permit Needed
  • Design Costs
  • The Estimated Cost and Value of Construction
  • The Square Footage Being Added To Build An ADU
  • Inspection fees and Additional Costs

Its recommended to always consult your trusted local ADU contractor to obtain permits. They will educate you on what permits are needed, assist with design plans and the right documentation to provide, the expected total ADU permit cost, and the timeline to be approved.

Examples of ADU Permit Costs in Los Angeles

Below are two examples given by the LA Department of City Planning of what an ADU permit cost in Los Angeles.

Detached ADU

Garage Conversion

  • Converting an existing garage to an attached ADU
  • 400 square footage
  • Project valuation: $20,000.
  • Total Permit Fee: $1045.22.

Estimated ADU Permit Fee Costs in Los Angeles

Below is a breakdown of the typical fees associated with ADU permits. Each area zone or city may have its own specific requirements and costs. These are general estimates and will vary based on the scope of the project.

ADU Design Costs

Once you figure out that you are eligible to add a unit to your lot, the first step is adequately assessing your design plans to submit for the right permits. Architect fees are generally between 5% and 20% of the total project cost.

Plan Check Fee

Homeowners planning to build an accessory dwelling unit will generally have to pay a plan check fee, or a fee to submit and check plans before application approval.

You can check an estimate of your total fees at the Los Angeles Department of Building and Safety (LADBS) website.

According to the permit fee calculator by LADBS, a 100k ADU Valuation gives a cost estimate plan check fee total of $991.62.


Building Permit Fees

Build permit fees range by project but the cost is mainly factored by the additional square footage added and project valuation. You will need a building permit to construct an ADU with utilities such as electrical and plumbing.

The average cost of a building permit in California is $1200. Build permits are generally between 5 and 18% of the total budget. Building permits may or may not include zoning permit fees and often include final permit fees upon approval.

ADU Impact Fees

Impact fees are charges from local agencies for the cost of public facilities. They are used to fund local infrastructure. This can include fees from school districts and for utilities, such as water and sewer.

The required impact fee is determined by the square footage of your ADU, or the average size of all the units on the lot. An ADU is exempt from impacts fee if it’s less than 750 square feet.

Depending on size, it’s possible that local agencies can waive impact fees.

Certificate of Occupancy

A certificate of occupancy (COO) is required before moving into your new ADU and can cost $150 per unit or more.

The Permit and Inspection Process

The city of Los Angeles has encouraged homeowners to build ADUs due to the housing shortage and increasing demand. New regulations have made it easier and faster to submit and receive an ADU permit.

The Los Angeles Department of Building and Safety (LADBS) requires homeowners to submit architectural and structural design and draws plans of the ADU they plan to build. You must also obtain and submit zoning, building permit records, and your specific property information.

Once submitted, your design and draw plans will then be reviewed for compliance with building codes and zoning laws. Once the plans are approved, homeowners can begin construction.

Inspections will be required for groundwork excavation and when all framing work has been completed. Plumbing, electrical wiring, and heating ducts will also be reviewed after they are installed and before the work is covered. Once construction is completed, there will be a final inspection and upon approval, a certificate of occupancy will be issued.

How Long Does It Take To Get An ADU Permit In Los Angeles?

ADU Permits are generally received within 2 months. According to the Los Angeles municipal code, permits are approved ministerially within 60 days from the date the local agency receives a completed application.