Got a Granny Flat? New Rules Are Here

Accessory Dwelling Units (ADUs) in residents’ backyards are altering the local rental market.

Santa Monica City Council approved new regulations for Accessory Dwelling Units (ADU) Tuesday, May 22, that come into effect July 12, this year.

An ADU can be defined as: “A dwelling unit providing complete independent living facilities that is located on a parcel with another, primary single-unit dwelling. ADUs have also been referred to as second dwelling units, in-law units, or granny flats.”

Accessory Dwelling Units (ADUs) in residents’ backyards are altering the local rental market.

Here are the key components of the changes from the City:

  • Maximum Allowable Size: The maximum allowable size for ADUs is now 650 square feet (SF) for parcels up to and including 6,000 SF in area or 800 SF for parcels greater than 6,000 SF in area. The Zoning Ordinance previously allowed a maximum size of 650 SF for all ADUs.
  • ADUs must still be clearly subordinate to the main dwelling unit on the parcel in terms of size, location, and appearance.
  • Second Story Size: There is no limit to the size of a second story of an ADU. However, the second story cannot exceed the area of the first story.
  • Conversions of Existing Accessory Buildings: Conversions of existing non-garage accessory buildings to ADUs are allowed. The Zoning Ordinance previously did not address this.

“ADUs continue to be excluded from R1 parcel coverage calculations per the R1 Interim Zoning Ordinance that Council adopted on April 10, 2018. The ADU development standards will be revisited as part of the forthcoming effort to review and update the R1 Single-Unit Residential development standards over the next 12-18 months,” according to the City.

A second reading of the ordinance will be heard June 12. If adopted at that meeting, the ordinance will become effective on July 12, 2018. More information: