MultiFamily ADU

Owners of duplexes, triplexes, and larger multi-unit buildings can add ADUs to their properties too. This represents one of the best opportunities available to increase net operating income and property value.

Options for ADUs on Multi-family Lots

Under current state law, there are two options for adding ADUs to multi-family properties:

 Conversion of existing non-livable space

  • Non-livable space in a multi-family property most commonly includes garages, carports, basements, or storage rooms. Properties with such spaces may be feasible locations for ADUs in the following quantities:
  • For properties with 2-7 units: 1 conversion ADU
  • For properties with 8+ units: 1 conversion ADU for every 4 existing units

Construction of up to 2 new detached ADUs

  • Under this option, a multi-family property owner can build up to two freestanding ADUs on their lot as long as required setback, square footage, and height limits are met. These units are similar in look and feel to detached ADUs on single-family lots, but can be designed in a way to match the aesthetic of your property. This option is not always feasible on multi-family lots that do not have adequate open space, usually in the rear of the property.

State law requires local jurisdictions to allow for property owners to do either one of these options, but it does not require them to allow for both concurrently. In many jurisdictions, however, you may do just that, combining both of these options to add both conversion ADUs and new detached ADUs. Our Adapt Feasibility study will help you identify the full set of options available on your property to help you maximize the number of units you may potentially add. Get a sample report.

Types of Conversion ADUs

Many of the same options for single-family conversions exist for multi-family properties: garages, basements, storage areas and others.

Options for ADUs on Multi-family Lots

Under current state law, there are two options for adding ADUs to multi-family properties:

 Conversion of existing non-livable space

  • Non-livable space in a multi-family property most commonly includes garages, carports, basements, or storage rooms. Properties with such spaces may be feasible locations for ADUs in the following quantities:
  • For properties with 2-7 units: 1 conversion ADU
  • For properties with 8+ units: 1 conversion ADU for every 4 existing units

Construction of up to 2 new detached ADUs

  • Under this option, a multi-family property owner can build up to two freestanding ADUs on their lot as long as required setback, square footage, and height limits are met. These units are similar in look and feel to detached ADUs on single-family lots, but can be designed in a way to match the aesthetic of your property. This option is not always feasible on multi-family lots that do not have adequate open space, usually in the rear of the property.

State law requires local jurisdictions to allow for property owners to do either one of these options, but it does not require them to allow for both concurrently. In many jurisdictions, however, you may do just that, combining both of these options to add both conversion ADUs and new detached ADUs. Our Adapt Feasibility study will help you identify the full set of options available on your property to help you maximize the number of units you may potentially add. Get a sample report.

Types of Conversion ADUs

Many of the same options for single-family conversions exist for multi-family properties: garages, basements, storage areas and others.

Find out what the ADU options are for your multi-family property.