Tips on Maximizing Los Angeles Multi-Family ADUs

Prior to 2020, Los Angles Multi-Family ADUs weren’t possible. This meant for multi-family property owners that they weren’t able to earn any extra money on their properties like single-family homeowners. Luckily, things have changed, and now multi-family property owners can benefit from adding ADUs.

One of the most important things to understand is what makes something a multi-family dwelling. It is not the zoning nor the property the structure is sitting upon. A multi-family dwelling is two or more residential buildings attached to one another. Think apartment buildings, duplexes, triplexes, and any other buildings with multiple units attached to each other. Based on the new ADU regulations, to add ADUs to a multi-family dwelling, it must be zoned residential, but the type of residential zone doesn’t matter.

How Many ADUs Can I Add to my Property?

In California, you can currently add a maximum of two detached ADUs. You also have the ability to convert accessory space inside your multi-family structure into ADUs. Be aware that different rules apply to each type of ADU.

A detached ADU is separate from the main multi-family structure. Some California areas allow for the two buildings to be attached, while others require them to be separated from each other. Detached accessory spaces, including carports or clubhouses, once converted, are considered to be one of the two allowable detached ADUs.

Even once you build the two detached ADUs, you can convert some of your attached accessory space into more ADUs. Attached accessory space if parts of the main structure that are not already classified as living space. Some examples include covered garages, basements, attics, storage rooms, utility rooms, or community rooms. Spaces classified as living spaces may not be converted into an ADU, nor can uncovered parking areas, including parking lots.

Use the Formula to Help you Add Multi-Family ADUs to your Property


If you are converting accessory space to ADUs in a multi-family structure, you are allowed at least one, in addition to the two detached ADUs. To determine how many ADUs you can add in terms of accessory space, the formula used in California states you can convert up to 25% of the number of units.

For example, if you own a duplex, triplex, or fourplex, you can build two detached ADUs on the property and convert one accessory space based on the formula. Once you own eight units, you can start increasing the number of accessory spaces you transform to two, but anything between five and seven is a grey area and must be left up to the local jurisdiction to decide.

Guidelines for Recommended Sizes of ADUs created from Accessory Space

When it comes to the square footage, there are standard regulations that most ADUs must comply with. They can’t be smaller than 150 square feet for a one-bedroom unit and can be as large as 850 square feet. For a two-bedroom unit, it can be as large as 1,00 square feet. In areas where no added limits have been put into state laws, an ADU can be 1,200 square feet.

Am I Required to Provide Parking when Building a Multi-Family ADU?

Parking doesn’t need to be provided when building multi-family ADUS as long as there is a car share within one block of your location or if public transportation is within half a mile. This holds true for any ADUs built out of accessory space and converted garages. But as a responsible landlord, you will want to think about where your tenants will park and how much parking is available.

Typical Cost to Build Los Angeles Multi-Family ADUs

The typical building cost for Los Angeles Multi-Family ADUs is per square foot. The cost to build a Multi-Family ADU is generally in line with the cost to build other ADUs. To ensure building costs will be cost-effective, make sure you are efficient in the way you are building.

Line up bathrooms and kitchens to keep plumbing and gas line costs to a minimum. Work out your design to help minimize the number of visits required by the city planner. Always think about your plan for connecting the utilities, as each method plays a different role in cost. Hooking up utilities separately requires the addition of a separate meter while including them in the rent allows you to skip that extra cost.

Use Experts to Keep up on Los Angeles Multi-Family ADU Laws

Although adding Los Angeles Multi-Family ADUs to your family property is a significant investment, it is not something you should take on yourself. The laws and regulations for ADUs are new and, therefore, continually evolving, so make sure you find yourself an expert specializing in permitting and designing these multi-family ADUs.

About Us

360Builders is a Los Angeles based construction company specializing in new construction, soft-story retrofitting, and multi-family ADUs. We pride ourselves on providing safe, cost-effective solutions to all our customers’ construction needs.

Recent Posts