Downey, California


In recent years, more and more people have been interested in building ADUs in Downey. The city has seen an increase in the number of applications for ADUs, and many people are eager to get started on their own projects. Cottage can help you start your project today!


All properties zoned for single family and multifamily use may be eligible to build ADUs.

Number of units

The number of ADUs you’re able to build depends on how your lot is zoned:

  • Lots zoned for single family use may add 1 ADU and 1 Jr. ADU (JADU).
  • Lots zoned for multi-family may add 2 new detached ADUs and at least one conversion ADU (interior conversion of existing building, but no more than 25% of the original number of units. (E.g. an apartment with 4 units may add 2 detached ADUs and 1 conversion ADU.)

Building size

  • The maximum size is 500.0 sq. ft. for a JADU
  • 850 sq. ft. max for a detached ADU
  • Attached ADU Max Size: 850

Building height

Building height for attached and detached ADUs is: 16 ft


Separate parking shall not be required for an ADU. However, the square footage of an ADU shall be included in the total square footage calculation to determine total parking required pursuant to Municipal Code Section 9708. Access to all on-site parking shall be provided from one (1) common driveway. This shall not preclude a circular driveway as allowed under Municipal Code Section 9710 – Residential Parking Design Standards.


The property owner shall record a covenant to the subject property that identifies the total number of dwellings units on the property, prohibits the units from being sold separately, and provides that at least one (1) dwelling unit shall be owner occupied.

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